get more ram.. this is the most important thing. so look for NB that can go up to at least 1GB.

get P4 or P-M (centrino) don't get Celeron.

look for intel chipset. 845 or 855.

harddrive: with mroe than 2MB cache. (some might have 5400rpm, but 5400rpm is NOT necessary faster than 4200rpm, for ex, Hitachi 80G 4200rpm is FASTER than toshiba 4019gax 5400rpm)