sylenth has a very fat core-sound and is easy to handle, massive seemed a little bit overkill for my cpu.

http://www.lennardigital.com/modules/downloads/

There is so many and there is some quality stuff in the free world, too!

Non-free: Predator, Phoscyon (303 on steroids), Albino, stuff from gmedia, Arturia stuff. I really woudln't know where to start. Depends what you are looking for and how much you want to/are able to tweak. Sound-wise sylenth really struck me.