Mainly here, although I've used to go on smaller forums about things I liked. I go on reddit and comment once in a while, but that's more of an exception than a rule.
For wow I pretty much only uses this.
I do look on other forums, like tomshardware , and a Danish side tweak.dk when I'm looking at hardware \ troubleshooting.
Private forum for members (former and current) of the French Foreign Legion (mostly to stay in touch with former comrades or to keep up with current events), and a few political forums.
twoplustwo forums. A poker forum with a good Science, math and Philosophy section. You can also talk about religion and politics unchained in their own subsections.