In no order of preference:
Lobby - Avenue/Bloor (decent food, great drinks, gorgeous people, highly recommended)
Panorama - Bay/Bloor (top floor patio of Manulife Centre, best Toronto skyline, good crowd, highly recommended)
Li'ly - College/Bathurst (haven't eaten here, but heard good food, great atmosphere, great drinks, great people, highly recommended)
Sassafraz - Bay/Cumberland (never been, and don't intend to, but Toronto's biggest celebrity hangout, if that's your thing)
7 West - Yonge/Charles (great food, great staff, very cool atmosphere, and best of all 24/7!)
As a side note, the best Chinese food in the city is:
New Ho King - College/Spadina (open till 4am on weekends, and have Singapore noodles, Shanghai noodles, General Tso chicken, and spring rolls to die for - it will be the last Chinese place you'll ever eat...it's probably one of the most popular after-club places to eat)
The absolute best Japanese, in terms of quality for price, is:
Sushi Inn - Bay/Cumberland (great service, *incredible* sushi - try the salmon sushi pizza, spider roll, dragon roll, and Hotate set - go on a weekend, and you're more than likely to run into a Maple Leaf or two!)