Blissey goes well w/so many cards it's not funny: Delcatty, Electivire, Raichu MT, Exeggutor MT, and I have even seen it played all by its lonesome. In the near-future, Weavile SW might even make a pretty mean combo with it. It's that flexible.
However, for all its speed, I do think it's a little fragile. There's a lot of good :fighting: stuff out there that can hurt it if they get it out fast: Kingdra ex d, Mario, Rampardos, and the upcoming Gallade card. It's all dependent who who gets out first.
- Croatian "moment of bliss" Nidoking