[TaLL|dUdE]

all of them are good enough for your needs i believe... but i suppose it would be better to get either the mid quad core or the higher one (for future proofing - by a few more months).

add a couple more hard disks as well i suppose as well. 1tb or a little higher if you're editing a lot of video.

would be better if you had a raid 5 setup too to keep your data safe.