Just setup my new Dual 2.7GHz tower with ATI X850xt card and Dell 20 LCD. The rest of the setup includes Logitech Z-2300 speakers (still in need of a little breaking-in), MX1000 laser mouse, and Kensington Slim Type keyboard.
First thing I did was *cough* borrow *cough* some RAM from work. Running at 5GB (2x1GB and the rest are 512MB), threw the 400GB drive from my iMac G5 in, set it as the startup drive, and I'm in business - only things I had to do was to set my monitor profile to sRGB since it auto-selected the Dell 20" profile.
This thing absolutely rocks. I had a Dual 2.0 when they first came out but had to sell it to buy a DVX-100 video camera. The thing chirped me to death. I'm happy to report that this Dual 2.7 doesn't make a squeak - no weird chirps, buzzes, squeaks of any kind. It's obscenely quiet - have it right on the desk and I don't even know it is there. I read that some people have the chirps still, guess I just got lucky.
The machine is somewhat old hat - you know the drill. It's fast. You definitely can't knock the PowerPC chips man, Photoshop 7 (my preferred version) starts up fast. Fast, as in I just think "maybe I'll edit a photo" and like, Photoshop is already open before I even click the icon.
The real gem in this machine is the X850 card. It's ridiculous. I play a lot of UT2k4 on a big 32-player Onslaught server (vehicles, the whole nine yards). Maxed out the graphic options, set it to full 1680x1024 resolution, and there's not even a hint of slowdown even in the most hectic situations. And the graphics are completely gorgeous of course - once you go widescreen you just can't go back. Sure my old iMac G5 was widescreen but I had to dumb down the graphics so much it wasn't even worth it. Verdict: pwn3rsh1p.

(the card does have a fan on it - even under pressure I can't tell when it's on, it's that quiet. Then again I haven't had a marathon 6-hour UT session yet...)
The Dell 20" screen is great, 'nuff said. I had to knock the brightness down to 40 to reproduce colors how I like them - but it's nice to know the brightness is there if I 'need' it.
And the Z-2300 speakers, if you read my previous post on them in Peripherals, rock. I ran some more tunes through them and it seems like they could use a bit more breaking in - I've racked up about 15 hours of break-in time and they keep sounding better. I usually judge speakers at the 50-hour mark; at the moment the sound isn't quite bright enough, but they'll get there and they will rock.
Now, I have a 9800pro card in my G5 at work that I occasionally fire up UT on. Is the X850 worth the extra cash? In my opinion, yes. Even if you're not a gamer, Motion loves the card, and for the extra $350 if you use any pro apps that utilize the video card heavily, it is well worth it!
So that's that - I'm not a benchmark kind of guy, since subjective experience is all that matters to me. And the thing is damn damn fast.
w00t!