i love mine. its a core 2 duo, 3gram, 3.xgzh
and hd2400,Games going COOL! Fast, nice looking
i have play all the last hardcore game. and i dont have any
problem playing. they go fast and sometimes i open them with high details
sound and video preform. are grate...for example, CAll of duty 4 goes prety fast in mine
with medium graphic detials, Games the i have play with the XPS:

All Steam Source Games
Crysis
COD 4
Lost Planet
Battlefield 214X
Battlefield
FlightSimulator X
GTA SanAndrea
Red Orchestra
Messia

about cd roms copy and movies and Videocapture.  its grate too
i work with audio and video editting and Animations and works grate
i can even Burn a Cd, Listen to music, Open the messenger, open explore
with Reason 4 and Adobe Audition working at the same time. and the computer dosent even skip or lag...
and the Online PINGS came down alot,bcouse the games are fast.

I'm not sure what the 105W stands for but... I bought an XPS 420 with a 22" widescreen ($1099.00) that came with an ATI 2400 128 mb video card that worked o.k. for stuff that did not involve a lot of graphics.

The computer itself has proven to be very fast and very quiet and since I replaced the video card with a ATI Radeon 3870, it does the little bit of gaming that I have tried just fine.

I've also added a M-audio PCI card and a couple of drives I rigged for a Raid 1 for data storage with a minmimum of fuss.  (I use the coputer primarily as a music server)  I think it's an awesome computer.

I do wish Dell would release a more flexible BIOS that would allow some tweaking.

As far as Vista is concerned, it works great but it takes  A LOT of work to get it to a usefull state.

You don't mention the memory or graphics card info.  If you're serious about gaming, then these specs are critical.  You'd need a mimimum of 2GB RAM, but preferably 3GB (or even 4GB, although only a portion of the 4th gig will be utilized in a 32-bit OS).  A 512MB video card would also be preferable, like the Nvidia 8800GT.

I have an XPS420 system that I use primarily for gaming, and it works great.  Most games can be played with high detail settings and run smoothly.

Going from XP to Vista is not really a "huge" difference.  It has a different look to it, but its still Windows.  You should be able to adjust quickly.

HTH

Grey Ferret