Alight, here's the deal, sparky (said in my best Jack Nicholson voice).
First, assuming you stay with Windows, there are several things you must do.
1. Completely reformat your computer. It sounds like you're dealing with a rootkit, and the only way you're going to see that completely taken care of is a fresh install. Any time you seem to have "killed" it, you've just sent it beneath the surface again. At that point, you may as well upgrade to Windows 7 and see if you like it.
2. Invest in some decent virus protection. I work in IT for both a university and a government agency; both require McAfee Virus Scan software on all of the machines connected to their networks.
However, you've peppered every post in this thread with ellipses, so that gives me the impression that you're really looking for some validation for your desire to switch to Apple products. Never fear! There's plenty of that to be found here, but I'm going to try to help you make an honest and objective assessment of your situation.
I assume you're a freelancer, and that this is your main source of income. Therefore, calculate an hourly rate (if you don't already have one), and see how much these virus problems have cost you. You're going to be out of commission for at least one whole day whether you stay with a PC or switch to Apple, so that loss in productivity is irrelevant.
Next, consider in numerical value what peace of mind is worth to you. It seems like your confidence in Windows as a platform is broken--like you'll be looking over your shoulder every time you use your machine, worrying about the next time a virus will strike. If going to bed at night completely satisfied that you've been productive today and will be so tomorrow is worth $1000, then factor that in to your decision.
If the math makes sense, then the decision is really up to you. If you make up your mind to get an Apple product, then you have a few more decisions to make.
The decision between 27" i7 iMac and Mac Pro:
I'm not going to lie, the 27" iMac is gorgeous, and I don't think you can go wrong. I'm not so sure about the finer points of color fidelity (I'm a hobbyist photographer and make do with a decent Samsung and my MacBook Pro), so that is something I think you should be absolutely certain of before you buy. You can also sit on the fence for a little while and wait to see if Apple refreshes the Mac Pro lineup soon. The way they are currently is an incredibly bad deal, and I wouldn't recommend that anyone buy one until the refresh. I understand that it's usually more important to have a huge amount of RAM than processing power when working with big photos (I generally work at somewhere around 7000x5000) and the i7 with 8 GB of RAM should work well for you.
If you are going to start working in video....ehh, this becomes a slightly harder decision. In either case, I would wait until the Pro hardware refresh, just to see what you can get for your money.
For a replacement laptop:
This machine probably isn't as crucial to you as your workhorse, so you might think of buying a refurb to save on cost. Also, there is at least one store that is selling the white MacBooks for $800, which is pretty absurd.
For a well kept Cinema Display and a Dell you can probably get close to $800 on Craigslist, so the MB will pretty much pay for itself.
Hell, if you're not going to be doing any work on the laptop, why not get an iPad? I'm going to be going down to the Apple store in 2:30 to try one out.
Some final considerations:
The screen tint issues with the 27" iMac have been taken care of. I don't think you have anything to worry about.
You will have to re-buy your Photoshop software for Mac. Sure, you could use your Windows copies, but then you'd have to be booting an iMac into Windows, and who wants that? If you have a friend that goes to uni, see if they can get you a cheap copy. My school gives them away for a song and a dance. You could also look on this as an opportunity to upgrade to CS5, which should be out shortly.
Apple does have a 14-day return policy on their computers. If you decide that you've made a horribly mistake, you will lose some productivity, but that is a fail-safe.
I'm not sure if I missed anything, but those are my thoughts.
Good luck making your decision, and let us know what the verdict is!
First, assuming you stay with Windows, there are several things you must do.
1. Completely reformat your computer. It sounds like you're dealing with a rootkit, and the only way you're going to see that completely taken care of is a fresh install. Any time you seem to have "killed" it, you've just sent it beneath the surface again. At that point, you may as well upgrade to Windows 7 and see if you like it.
2. Invest in some decent virus protection. I work in IT for both a university and a government agency; both require McAfee Virus Scan software on all of the machines connected to their networks.
However, you've peppered every post in this thread with ellipses, so that gives me the impression that you're really looking for some validation for your desire to switch to Apple products. Never fear! There's plenty of that to be found here, but I'm going to try to help you make an honest and objective assessment of your situation.
I assume you're a freelancer, and that this is your main source of income. Therefore, calculate an hourly rate (if you don't already have one), and see how much these virus problems have cost you. You're going to be out of commission for at least one whole day whether you stay with a PC or switch to Apple, so that loss in productivity is irrelevant.
Next, consider in numerical value what peace of mind is worth to you. It seems like your confidence in Windows as a platform is broken--like you'll be looking over your shoulder every time you use your machine, worrying about the next time a virus will strike. If going to bed at night completely satisfied that you've been productive today and will be so tomorrow is worth $1000, then factor that in to your decision.
If the math makes sense, then the decision is really up to you. If you make up your mind to get an Apple product, then you have a few more decisions to make.
The decision between 27" i7 iMac and Mac Pro:
I'm not going to lie, the 27" iMac is gorgeous, and I don't think you can go wrong. I'm not so sure about the finer points of color fidelity (I'm a hobbyist photographer and make do with a decent Samsung and my MacBook Pro), so that is something I think you should be absolutely certain of before you buy. You can also sit on the fence for a little while and wait to see if Apple refreshes the Mac Pro lineup soon. The way they are currently is an incredibly bad deal, and I wouldn't recommend that anyone buy one until the refresh. I understand that it's usually more important to have a huge amount of RAM than processing power when working with big photos (I generally work at somewhere around 7000x5000) and the i7 with 8 GB of RAM should work well for you.
If you are going to start working in video....ehh, this becomes a slightly harder decision. In either case, I would wait until the Pro hardware refresh, just to see what you can get for your money.
For a replacement laptop:
This machine probably isn't as crucial to you as your workhorse, so you might think of buying a refurb to save on cost. Also, there is at least one store that is selling the white MacBooks for $800, which is pretty absurd.
For a well kept Cinema Display and a Dell you can probably get close to $800 on Craigslist, so the MB will pretty much pay for itself.
Hell, if you're not going to be doing any work on the laptop, why not get an iPad? I'm going to be going down to the Apple store in 2:30 to try one out.
Some final considerations:
The screen tint issues with the 27" iMac have been taken care of. I don't think you have anything to worry about.
You will have to re-buy your Photoshop software for Mac. Sure, you could use your Windows copies, but then you'd have to be booting an iMac into Windows, and who wants that? If you have a friend that goes to uni, see if they can get you a cheap copy. My school gives them away for a song and a dance. You could also look on this as an opportunity to upgrade to CS5, which should be out shortly.
Apple does have a 14-day return policy on their computers. If you decide that you've made a horribly mistake, you will lose some productivity, but that is a fail-safe.
I'm not sure if I missed anything, but those are my thoughts.
Good luck making your decision, and let us know what the verdict is!