I personally like Blissey/Delcatty the best (I'm a setup kind of guy), but I think Blissey/Lucario was the best play for BRs, as Kant said earlier. T2 Blissey is great, but I'd say it ranks behind the two I mentioned earlier (not that others haven't been successful with it). Blissey/Electivire is my least favorite, and probably the least viable. In my experience it's the least consistant of the four. Electabuzz starts are terrible, and if you run a few turns without a supporter the deck won't sustain itself like the other three variants can.