There are the place i've been to and would go again, maybe
Byward Market
The Whiskey Bar is pretty good.. 21+ crowd
Space is a meat market - go there at your own risk of being grabbed in the ass
Club MTL has a hot asian coatcheck girl so i've heard :lookarou
Helsinki's - located in the court yard. Slightly pricy, but a very nice chic lounge.
Hull
426 - Just off highway 5, probably the classiest place in the Ottawa region. $10 cover
Elgin Street
Griffin's good crowd, reasonable cover
Nepean
Le Scratch - Huge nice pool hall, extremely big dance floor, but nobody's friggin there! They play Hot 89.9 stuff. Is that why nobody goes?
Vox Lounge - haven't been there in ages, but was pretty good last time i think. Lots of teenies.
Kanata
Karma Lounge - good west-end crowd, no asians though
O'Connor's Irish Put - Live band, all white