Tower Defense Style PC Games?

[Lovelocke]

About to finish Crystal Chronicles for the 360, absolutely loved it. Played a few flash-based browser games that ranged from "workable" to "ick", but wondered if there was ever a super nice PC Tower Defense style game that say, utilized mah Quad Core and Geforce 9800?

 

[Zayren]

Plants vs. Zombies is awesome, but it won't utilize your PC like you want.

Still awesome, though.

 

[Jandau]

Plants VS Zombies is brilliant.

Defense Grid: The Awakening sports some nice graphics and is a solid game overall.

Gemcraft (1 or 0) is a Flash game, but is one of the best TD games ever.