I don't have a preference, so here's my input/summing up my favorite things.
Sandy Bridge Q1 - They're a significant improvement over the last generation of intel's chips, but not anything too amazing. They seem to have great overclockability and stability, but the process of getting them to that stability seems tedious.
Bulldozer - Their new architecture splitting off the cores into sets of two is genius. It's like hyperthreading, only without the performance loss from virtualizing. Dual-cores are one of the most significant performance increases we've seen and Bulldozer is truly taking multiple dual-cores and having them work together, but in independent pairs. Hopefully 990X will give these things the performance their potential deserves.
Q3/4 Sandy Bridge - These will include more core count and a vast performance increase. This is more like the 920-980X line being upgraded. The Q1 i7s are too close in performance to the Nehalem i7s, so I don't consider them true i7s unless they're strictly talking about i7-860/870 upgrade.