first off, i would NOT go with the biostar motherboard. you are so much better off with asus.
secondly, you don't need 2 gigs of ram. 1 gig is plenty for your stated needs. go with corsair XMS, 2 sticks of 512MB (for dual-channel operation) will run great and cost about half as much.
do not forget to allow yourself money to acquire windows and/or the games and programs you plan on running. windows XP home OEM costs $90, pro is $130. personally, i would spend the extra money and get XP x64, for $130. this enables you to run 64-bit versions of games you either currently own or will own in the future. remember that using xp x64 requires ALL device drivers to be 64-bit, so don't plan on throwing older hardware into a system running x64 unless you can get 64-bit drivers for said hardware.