Do you plan to overclock? If so the 760k would be the better choice. It might cut in to your budget though because you'll need an aftermarket cooler and a fairly decent motherboard to get good results. If not I'd go with the 4130. It's a good budget processor and I think you can get it at tigerdirect right now for around $ 100.
I'd say the i3, it's very decent, don't let the 2 cores make you think it's any worse than the 760k's 4 cores. It also gives you a much better upgrade path for the future, as well as a better selection of motherboards
Keep in mind that 4 AMD cores = 2 AMD Modules, which don't have two of a lot of parts earlier on in the pipeline, so it's not four complete cores either. This causes different bottlenecks than hyperthreading, but the i3 has much better single threaded performance anyhow and so it wins out overall. heck, people compare the i3 to the FX 6300, not the 760K.