I just did the same thing myself. I wouldn’t get hung up on only getting an Intel chip…I used a AMD Athlon 64 X2 4400+ on a ABIT Kn8 Ultra mobo and it’s more processor than After Effects and Premiere Pro 2.0 will use combined for the most part. I would recommend getting as much ram as you can. My secondary internal drive is a RAID array, but it sounds like you’ll be handling most of your files externally. I really don’t have a video card either…just a cheap model that supports high rez…no problems scrubbing through video, only mild delay on complex frame renders in AE.
One thing I think a lot of people overlook is the power supply. I wouldn’t cut any corners there. If money is not an issue, get the most expensive power supply you can afford.
-Dan