I hear warmachine is pretty good. I watched a game of it the other day for the first time, it looked good. The minis rock too!
There is also Hordes, the fantasy version of the game that shares a lot of the same rules.
It's OOP now, but I really like the Starship Troopers game. I'm not sure what happened to it, but my guess is lack of support on both sides of the coin. It had some interesting game rules. It was a blend of turn based gameplay and impulse. You fought as a unit, and when other units approached you could "react" to them. There were only three playable armies though, but there was a fourth one in the works just as it got the axe.
Now I'm stuck with all the minis with nothing to do with them.
I even tried to eBay them at one point, for a huge loss, and still nothing. Maybe I'll donate them to some charity. "Table top battle games for the homeless." That'll teach'em!