Supahos :
I assume you mean best CPU... I assume since you're buying for them then you don't want to OC it yourself... so its about a coin flip between a I5 4670 (non k since I don't figure you're gonna OC) and an FX 8350 (would say 8320 but if you don't plan to OC it then you might as well start faster). Either should do the job very well and for a very similar price.
The Intel processor is $20 more, what does it do differently? I'm new with PCs. Also they do have a 10% or 20% overclock would you recommend that? I heard that The 8 core AMD is not necessary unless you render or do anything of the sort (which I don't, so would it be a good choice. I do have fraps though, because I have recorded small things on minecraft and might record...