World of Tanks and League of Legends.
OK so far I've enjoyed World of Tanks. Its a Call of Duty-esq (tanks only though) style game. You play on large maps against other tanks. You can play as German, American or Russian tankers. But the battles are mixed so you are playing on teams with all three factions on the same side. There is some sort of balancing algorithm at play in the game in terms of tank types (a mix of light, medium, heavy, tank destroyers and mechanized artillery) and I think it includes peoples crew training, upgrades, etc. in the balancing equations. So the games are mostly balanced and generally fun.
So far my only complaint is the leveling is really slow ... clearly they want you to pay for the bonus experience. But I've heard in the game and on the forums that even with the premium experience its an ultra grind. Really though as far as microtransaction goes you are only mainly looking at buying quicker leveling not really additional content as far as I can tell.
World of Tanks Trailer:
Ok the second game is League of Legends its apparently based on the Warcraft III engine (ya I know blast from the past eh!) but I've heard its fun. Your basically rumbling around with a single hero in a big battlground (again just think Warcraft III) where you fight either 2 vs. 2 battles or 5 vs 5 (or you can just fight the computer for a reduced exp reward). Apparently they rotate the hero types each week and if you want to keep playing the same hero type you have to buy it. I don't know what other microtransactions they have going on ... I haven't played it yet I've just been hearing about it. I'm actually downloading it now and I'll update this post when I get some playtime in. Update: Been playing the game for a few hours, its pretty cool so far. Worth a look anyway.
League of Legend trailer 1: