Torchlight is good if you like Diablo style RPGs. It basically is Diablo but with a pet. Review [http://www.escapistmagazine.com/articles/view/editorials/reviews/6697-Review-Torchlight]
Killing Floor is a budget version of Left 4 Dead. Review [http://www.escapistmagazine.com/articles/view/editorials/reviews/6099-Review-Killing-Floor]
If you're into indie stuff then many of those have mac versions eg Braid, Machinarium and World of Goo.
And as you've played all those games I'm guessing you've got an Intel Mac. Any reason in particular you're choosing against the bootcamp route?
Killing Floor is a budget version of Left 4 Dead. Review [http://www.escapistmagazine.com/articles/view/editorials/reviews/6099-Review-Killing-Floor]
If you're into indie stuff then many of those have mac versions eg Braid, Machinarium and World of Goo.
And as you've played all those games I'm guessing you've got an Intel Mac. Any reason in particular you're choosing against the bootcamp route?