I'm not a massive fan of forums in general, but that is mainly down to the horrible forum software that is out there. The software we use here is actually pretty good, for Q&A at least.
I created a Q&A site because I wanted to do something a bit different and unique, that hopefully people get something out of in the future (e.g. looking up information). That's different to a forum where after a few weeks or months, the discussion is not worth reading through.
However, I do think a more open-ended discussion area would be good for this site because not everything is a black and white "this is the correct answer" type thing. The chat room serves this somewhat, but often people just want to read a few comments and leave their reply, not all having to be online at the same time.
So it's certainly possible something will happen in the future. I'm very likely going to add a poll section which should serve part of what a forum does. After that... we'll see!