For food in Montreal, I recommend Schwartz's (probably the best smoked meat deli in town) and La Banquise for poutine. There are also lots of fantastic little pubs and hole-in-the-wall restaurants if you're willing to try 'em.
As for the activities, I think you've basically got them covered. Old Montreal is definitely a neat place to wander. Just watch out for all the stupid touristy crap that's been sprouting up rather quickly down there. And the clubs... well, I never experienced any bouncers or dancers trying to take my money, but I've always been under the impression that if you try to at least attempt to speak some French (even if it's only to say you don't speak it), they'll probably be less inclined to try and rob you.
