Here is my favorite fast basic computer. The new i7-4790k is amazing. Add video card, more memory, larger heatsink/fan and larger case as needed.
I think I might build something like this for my dad somewhere down the road since he's one of those non-tech-savvy older guys who are still running ancient PCs.
He would be blown away by how much faster this would be for his basic internet/e-mail/news streams.
The power supply is a little overkill but would give you plenty of headroom later to add a discrete video card. You could get away with a 80+ Bronze Corsair or SeaSonic and save a few bucks.