Dawn of War II: Tyranid Fear (or lack of)
I have become hopeless addicted to Dawn of War 2 recently (I liked the first game but this is really a lot more like a sci-fi squad warfare RPG than the RTS original).
However it does have a slightly weird thing going on where Tyranids weakness to flames makes them the easiest enemy to fight. As long as you have some melee competency I find myself romping through Tyranid levels.
By contrast, Eldar seem to be the most difficult enemy to kit the team out for as they contain range, melee and vehicles. I would have thought that plasma weapons would have been the answer but so far all the plasma weapons I’ve found are very slow and not very high damage.