I can also recommend the Fairfield Inn by Marriott (which Karl G mentioned above) on Berri near Rene Levesque. It used to be the rather run down Lord Berri but has now been transformed into a very nice place within easy walking distance of Campus and
Stock. Room rates are quite reasonable.
I stayed here a few weeks ago and incidentally had a very nice time at Campus. Contrary to reports elsewhere on this site, it was quite busy on a Thursday night with plenty of dancers of all types. Alas, it'll never be like it was in the 90's however.