I was wondering if there are more Tower-defense-fans on mmochamp. My friends and I started playing ye old Elemental TD 3.0 again since wow is a bit calm at the moment. Loving it!
There are also some new Starcraft Element TD maps, so I've heard.
I strongly recomend you*Defense Grid: The Awakening, avaliable on xbox 360.
Apart from that SCII have great mods for tower defense lovers, elemental and others exported from old warcraft 3, and there are some new mods really cool. Bardrok tower defense is the one i play more, really well balanced and some cool towers, also with the adition of traps to the arsenal.
Thats for serious gaming :P
For the lol you have the Bloon tower defense series is a web based series of games wich are cool for having a good time far from home. Also another web based game wich is great is "Dont touch my gems" you can google them to find.