First to fans and noise....
I built it in a fairly standard case and the temps were fine and it was very quiet indeed (ASUS Qfan drops all motherboard controllable fans to basically idle, and spins them up only if needed), but I got to thinking...."what happens when I stick another 4 hard drives in, and a second videocard?" (the answer being, "it's going to either melt, or stress the fans until you lose the will to live cos of them wobbling and whining".
I then built a machine for a cow-orker using this........

3x120mm fans
1x200mm fan!!! (like you said, a helicopter)

So I got one too, my temps are now stupidly low (CPU, which is the legendarily hot Athlon variety, barely hits 40 degrees under load), and with the fans on the lowest of their 3 settings (except "blue thunder" up top, which is on full blatter) it's unnervingly quiet, though certainly louder than the 24/7 linux box, which I've beaten to a near mute. Going to get a fan controller for it, so I have full range from off to concorde takeoff. Glad I built the machine for that guy cos I would have never bought a "gamer case".
As for TFT's, well, yes there are still some issues with sub native resolutions, but if you remember to hit the "auto" config button after you switch most of them vanish. It's also worth knowing that they tend to have a higher dot pitch or lower dpi, whatever way you want to look at it, so for the fine digital artist they are a bad idea (unless you have a big chequebook). The payback for the downrezing bugs is that you can fool the buggers into almost any res if you try hard enough. My linux X server refuses to let me step through the modes on it....cos it doesn't actually report any to the computer, although it maybe due to there being a KVM in the way (a KVM more over which does not support so high a res).
Mine does 1680x1050,which sounds high, but it's really only stretched 1280x1024. Getting one that goes higher than that is pricey. Physically it is (screenwise) a bit less than an inch taller and a heck of a lot wider than a 17".
TFT's do have their other quirks, their "switching time" from black to white to black is somehow crapper than CRTs though I know not why, so sometimes fast motion can look a bit blurred.
Some games do support widescreen res, mostly more modern ones obviously. Those that don't behave like a widescreen TV and use streched pixels to fit a 4:3 res onto a 16:9 16:10 14:9 whatever screen, some people hate this, I love it, it looks great in racing games. You can force it not to do that easily on ATi cards and with some thought on NV ones.
If you can get one for fuck all like I did (200 knicker, thhangyoooverrrymooch), go for it.
***NOTE**** to ANYONE thinking of getting a screen to share between a computer and TV duties, do *NO*T* buy a tv with a computer input, TV's even so called "HD" ones have appallingly low resolution compared to even basic PC monitors. If you want the one screen that fits all, buy a big monitor and a TVcard for the PC (if you have SKY or a VCR, you will want one with an analogue input, if not, you can just get a pure digital one, shove an aerial up it's hole and enjoy freeview (and the ability to dump the raw mpg to disc....errrrm in linux anyway, good luck with that in winders)