well its not only that. windows 7 uses less ram than vista and xp so more ram usage goes to what your system is actusally doing rather than maintianing windows. yes you have other OSs at your disposel but windows 7 seems to be the more applicable to what your purpose is. so from what i gathered together so far im totaling out at 1600 bucks for the whole computer building it myself. parts include:
asus z77 motherboard
3.4ghz i7 2nd gen.
16gigs of ram
1tb hard drive
one or two gtx 560 tis
850 to 1000watt power supply
asus dvd rom
random gaming keyboard/ mouse from logitech
samsung 24 120hz refresh LED monitor
some random case for 80 bucks with 120 mm fans all around
and a basic 2.1 sound system
Now i did find all this stuff on amazon.com which they seem to be preety good on pricing.
regards,
drakkhen20