From the Blood Angels teams, Chaplain's team is my favourite.
Purple from Dark Angels - I know that it is just luck-based, but rolling a 5 on a Deathwing Attack agains a swarm of 5 GS is priceless.
I find that specific teams don't matter all that much. It's really about the combination of teams. I've had games go so easily I thought I was breaking rules because of the lineup I had, coupled with lucky dice rolling. I've also had those games where individually strong teams don't work well together. Having teams that have really powerful attacks is great, but having a combo of teams with powerful abilities in support and move + activate is massive when matched with powerful attack teams too.