I don't think that building a system is that hard, i'd go for a phenom II x4 processor, and 4 GB RAM a good ATI HD video card and any mother board that supports that, and maybe you could try one with a cooling system.
I like AMD and ATI because they have a decent performance relative to its price, compare to Intel and nvidia, they have better performance but also high price.
But after all, its just my opinion and what i'd think is good, might be wrong :P
~Coalwater~