I don't know much besides the current flavors at tournies.
What iv seen is...
Vulkan with TH/SS termies, many bikes and speeders with flamers and multi meltas (id make this if I played marines)
shriek with massive termies, trifecta of landraiders.
The popular non gimic vanilla list seems to run pedro (vote for pedro!)
The tacticals seem to always have something like, plasmacannon,plasmagun and Pfist, not really sure how thats optimal for SM but im a guard player so we don't really mix and match.
A pretty solid tactics for shooty tactic squads is hugging ruins. power armor is cover is difficult to remove and makes even the simply tactic squad a pain. Not to mention for guard where our only viable AP3 comes from tanks and trying to remove these guys with plasma is a big double edge.
i'm probably telling you stuff you already know but I'd figure I'd post just in case.