Seriously, That X-fi is junk for the price, go with the X-Fi gamer, save the money, SERIOUSLY GET THE BETTER MONITOR. Samsung 24 inch is SWEET.
You and I have almost the same build, We should really trade emails or something and talk about what we are doing, i will send you a Private message in this forums.
As for the CPU, its tops for the price, you don't need anything more. Get the GTX, be happy with it and then buy a better one in about 6-8 months and be happy with that. you monitor is where most of your gaming pleasure is going to come from. I have the Samsung 244t and about to buy the Sharp 32 inch 1080p hi def LCD for duel monitor. That sound card is truly junk atm. Dont waste the money on that, get a phat monitor. Your onboard sound is just fine, unless you are an audiophile like me, then you need to go to a pro sound card for about 400-500 US dollars.
now, about the motherboard. You basically have 3 choices at that level. The one you have listed, The ABIT P35, or the Asus P5K Wifi.
Gigibyte is very nice and kinda of for the serious overclocker. Its kinda of a tough board for the novice OCer
The Abit is simple and effective and the cheapest of the three, with less thrills, but really does a great job, OCing is a charm on this board
The Asus is in the middle of those two but has Wifi and is a tad more expensive.
These are only my impressions from TONS of research.