As previously said, AMD will be releasing 6-core CPUs soon enough. Intel only recently released the i5s and i7s so I would only expect moderate increases in speed and stepping for now. Of course Intel will trickle down 6-core CPUs to lower price points if they see AMD created a demand for them. As for new architectures, nothing new till AMD releases Bulldozer based CPUs.
Not sure I'd do that. IF AMD can release a 6 core part in the $200 range it might be better then the i5 750. It's rumored to be a 2.6 or 2.8GHz part and will have more cores to combat the i5s higher IPC. Seeing as its supposed to be coming soon, I myself would probably wait to see who comes out on top.