at this point cpu speed never seems to be a big issue, I have an older one but it runs fine, Im more worried about ram and the video card. Granted faster cpus are useful, but not really the same gain over more ram and better video cards, also if your doing a lot of large file work a faster hd is useful. I'd go with a dual core 64bit processor at least 2.2ghz. I'd go with an nvidia geforce 8500 or better or an radeon hd3xxx or better. the geforce 8500 might be a little slow so you might want something better if your not going ot have a dual sli setup. as far as memory I'd say stay with 2 if you have win xp, or 4 with vista, either way ram is incredibly cheap nowadays.