For gaming, AMD seems to have the edge. what speed? as quick as u can afford i have 3.0 ghz P4 and i run the newest games in high res no problems. Dual core: not worth it (yet)
Graphics card, i can recommend the XFX Geforce 7900GT XXX. Just got one myself today and man it is quick...
Motherboard, i always use ASUS and never had problems.
1gb of DDR400 at least LOL

HTH