OP,
You have received quite a great amount of advice, since I posted earlier in the thread. As
Firestarter, so eloquently pointed out, RAID is not Back-up per-say, rather it is a storage solution. I use various RAID configurations, because they work for me. I went with RAID 1 & RAID 1+0 (10) storage setups, because they are what works for me & my work-flow. I shoot way too much, to be using DVD's as a storage solution.
From my experience, I have yet to encounter someone, that has a had a CD/DVD last more than a Decade. IMO, that type of statement is not valid, till we've had DVD-R's for two decades or so, and can prove that they are still readable years later. Lab Testing, doesn't count for crap in real life.
I bought my Mac Pro on eBay, and have yet to encounter any issues with it. It is a 1st Gen (1,1), and has worked flawlessly. After I received it, I added 12GB of Ram, and re-configured the HDD Bays for my needs.
Bay 1: 250GB for OS, Documents, & Apps
Bay 2: 1TB 7200, for Scratch and only Scratch. I have it setup for both CS5 & Final Cut, but that's it. I do not use it for anything else.
Bay 3: 1TB 7200. OSX RAID 1
Bay 4: 1TB 7200. OSX RAID 1
Both 3 & 4, are linked together via OSX, in a RAID 1 Configuration. I use the RAID 1 primarily for active files that I am rendering/ working from (i.e. Images & Videos), however, I also make a clone of the 250GB HDD, that I regularly update, as files are created/ edited.
Though
Designer Dale, pointed out that I am a Pro, I also started out learning the ropes through mostly trial & error, of what to buy & what not to buy. That is a rather expensive road however, and forums didn't exist back in the late 90's & early 00's, like they do today. Whether your a Pro, a Hobbyist, or a Beginner, it doesn't really matter when it comes to storage. Storing & backing up Images/ Videos/ Files, is just part of the modern digital age. When I am asked about cameras' to buy, I suggest to anyone, that is looking to invest into the newer DSLR's/ HDSLR's, to also invest in large HDD's to back up the rather large images, that are captured by the newer bodies.
Snberk103, has hit the nail on the head, regarding his most recent post. Mac Pro's are typically a longer term investment. Though I bought a 1st Gen, it is quite sufficient for running CS5 in 64 Bit, and Rendering video in Final Cut.
Here is an example of daily usage on my MP: I typically have 6-10 Apps running at any given time, and though I have PS CS5 maxed out, Ram allotment wise (80% of total Ram), I never max out all 12 gigs. Highest I have ever hit, with both CS5 & FC running @ 100% + FireFox & PhotoMechanic is 9 of 12GB. If I leave FF running for days on end, then it will consume 1-1.5GB of Ram on its own, and I will start getting paging issues on certain sites. Even though the MP is a 1,1, it is expandable to 32GB of Ram.
I also have a Spring 2008 24" iMac (2.4 C2D, 4GB Ram, 250GB HDD), and it does well running CS3, FF, & PhotoMechanic. But the iMac is nearly maxed out Ram wise, and doesn't offer the expandability of the Mac Pro. However, since I bought the Mac Pro, the iMac is resigned to light duty, as it just doesn't stack up to the Mac Pro, though the iMac is several years newer.
The suggestion for an LCD to compliment your Mac Pro investment, is quite an important area to look into. I currently use the last generation of the 23" ACD. Color Accuracy is dead on, however, when I start looking for a replacement, I will be looking towards both the NEC PA Series Line-up (
http://necdisplay.com/category/desktop-monitors) & also the Dell UltraSharp line-up (
http://www.dell.com/content/topics/.../landing/en/ultrasharpmonitor?c=us&l=en&cs=04).