Well I want the computer for, photography, some games, music, internet/e-mail, money/date management and some basic word processing tasks, nothing really intense or heavy (although I guess you could say Photography is)
Okay, now we're talking.
For the photography, internet, music, e-mail, etc, the Mac will be amazing. I suspect you'll really enjoy the offerings in these areas. They're very easy to set up and use, and I found myself at home right away with them. iTunes is at home on a Mac, obviously.
Photoshop works pretty much the same on Windows and OS X, but it just feels very at home on a Mac in a way that it does not on Windows. iPhoto is great for basic photo management, and Aperture, Lightroom, and a new open-source (free) competitor are all very nice for advanced stuff (mostly differentiated by volume... they're very suited to you if you take many, many pictures).
The Safari browser is very nice -- my personal favorite of any available option. Firefox is also available, and I use it occasionally on OS X and exclusively on Windows. (I personally prefer Safari to Firefox, but opinions vary on this).
Apple's built-in Mail, Address Book, and iCal scheduling program are all pretty straightforward, and I generally like them. Probably the best thing about them coming from Windows XP is that they're integrated with Spotlight searching (although I'm sure in Vista it's quite similar).
For the money -- I don't use any sort of financial software, like Quicken or MS Money. I've heard anecdotally that some people are not happy with Quicken, particularly if they're coming from Money on Windows. But I'll defer to someone who uses these programs more.
For Office tasks, you have a couple of options that have several threads devoted to them. MS Office is due for revision around the beginning of the year. The revision is somewhat controversial... if you've seen Office 2007 on Windows, you have a basic idea of what I mean. The Mac version seems to be more sensible than the new Windows version, but... As for the current version, Office 2004 personally to me is the best version of Office I've ever used on either Mac or Windows. The only issue is that it runs under an emulation type of system because it was written for the processors Apple used before they went with Intel. The other major option is called OpenOffice (and a variant called NeoOffice). They're free, your mileage may vary. I personally don't find them satisfactory, but many others like them. If you don't collaborate with other users who share and edit your documents, OOo or Neo are probably very good options.
For games, you have a couple of major options... one is certainly to get a copy of Windows (either XP or Vista) and install it on the Mac. There are Mac games, and where they exist, they tend to be excellent, but the selection is quite limited. If you get an iMac, it should be fairly capable generally with games (considerably better than that specific XPS model), and it should generally scream in Windows XP.
Overall, I'd definitely think about your software budget... you sounded skittish about money to begin with. If you get a Mac, you're probably going to need software... the things you'd probably need aside from iLife...
- Photoshop (if you have a relatively recent license, i.e. CS3 and maybe CS2, you are usually eligible to "crossgrade" to the Mac version for a very small fee), Photoshop Elements, Pixelmator, etc, something for photos
- Money software, since you mention it
- Office software, possibly
- Possibly a license for Windows to run on it.
for the win
