Well, lets see. The Asus Deluxe isn't a bad motherboard, go for it if you can afford it.
The 3800+ is a great clocker, so yet again, go for it if you can afford it.
As for the sound card, I dont think you need something *that* high end, an Sound Blaster Audigy2 ZS wld be better imo. The Xfi's have crackling issues, etc. As for XP-Home, Newegg.com has it pretty cheap.
As for the 3700+, prolly around $100.
You can get all the parts + XP Home at Newegg.com Good luck!