as a very experienced builder, I would change alot
the lcd you linked to, from test results of its older brother the l226wq , probably has substantial input lag, which is not something you want for games.
it is not easy to find lcds that have almost no input lag, but I think in general you should avoid displays that have response time conpensation... that is... the ones that claim 2ms response times... those aren't real... they are 5ms response time displays with added circuitry to eliminate blur... this circuirtry takes time and concequently delays the image before it reaches your eyes... obviously not good if you are playing a fast paced game where things like twitch are important.
that ram is shit, it requires 2.1v just to operate, get 1.8V ram. this might start a flame war, but seriously, Jedec spec is 1.8V for ddr2.... so people like crucial and corsair over-volt the chips to achieve better timmings or frequencies... obviously this lessens the life of the component.... and in my expeirence, if you wanna overclock you can take a 1.8v dimm and get great performance out of it by upping the voltage... specifically i would recommend the mushkin heatsink-less 1.8v ddr2-800 2x1gb kit currently at newegg for like $92.. maybe get 2 of them for 4GB of ram.
skip on the wireless mouse,,, annoying to worry about batteries and when they die mid-game... you lose. plus performance is never 100% of a wired mouse, something crucial for games. I use a microsoft laser 6000 mouse, and love it,, but lots of choices out there... just get one that's wired.
new motherboards have hi-def onboard... try it out before you dish out almost $200 on that audio card... they can be very high quality and almost free. not all hi-def chips are created equal, id have to check on that gigabyte, but the p965-dq6 board used a realtek chip, probabaly the worst hi-def chip out there. choose a p35/g33 motherboard with good onboard audio.
the speakers you chose have a digital input... so you wont see any difference in sound quality between the $200 soundcard, and onboard audio.
if you don't wanna overclock, and really ... well given your situation i'd say dont bother, you can afford a fast quad-core chip and never worry about stability.
well as i was saying, if you dont wanna overclock look at these motherboards:
http://www.newegg.com/Product/...x?Item=N82E16813121314
or
http://www.newegg.com/Product/...x?Item=N82E16813121316
both about the same except one is a g33 board, has onboard video,, and is matx... onboard video is useful once in awhile if your video card is having trouble or whatever,, anyway its free and you wont be using it 99% of the time.
the thing about these intel boards is quality.
startec hd-audio (very nice)
intel gigabit ethernet (best in class)
texas instruments firewire (best in class)
these boards.. when a new bios is out, comes in the form of an executable... that u can run in all flavors of windows including vista64.. and itll just upgrade your bios,, no running around for special utility programs or floppy disks... also comes in bootable iso and bootable usb key... so , well thats ideal.
anyway the os.. get windows vista ultimate x64... its better.. maybe not a lot better than 32-bit but, it is better.
the hard drive, seagate 7200.10... why? its slow and not too quiet.
get the samsung T166 500GB sata drive for $110... its the quietest one around also faster than the seagate
or get the hitachi T7k500 drive... for $105 from zzf... its the fastest non-raptor around, also quieter than the seagate and also has 166GB platters.
the heatsink-fan that comes with the xeon is pretty good, very quiet... unless your overclocking or have some wierd case that doesnt have ventalation,,, or live on the sun, you do not need an aftermarket cpu cooler... stick with stock, at least at first, its really not a bad cooler... very quiet.