Queen St West for shopping. Used to be more small boutique stores, but there's all kinds of stuff there now on the stretch between Spadina and John.
Definitely check out Club Bass, but mind the odd hours. Lots of Lakland, Roscoe, Bergantino, and MarkBass stuff on display to try out.
If you're into r&b/funk/Motown covers and good food, go to Joe Mama's on King St West on a Friday or Saturday night. The house band ("Shugga") is an amalgam of some of the city's best session players. On a night when they're not touring with the likes of Jully Black, Divine Brown, etc., you'll find some monster players, including Calvin Beale and Juwayon Clarke on bass. Incidentally, Cal plays a BN5.
Speaking of monster players, Toronto is home to virtuoso electric bassist Rich Brown, who usually does a Saturday night gig with the house band ("The A Team") at The Orbit Room. Again, mostly r&b/soul covers. Doesn't really do full justice to Rich's skills (for that, you'll have to check out his jazz/fusion band, rinsethealgorithm) but still awesome live music. (Rich is all over different concerts on the CBC Radio 2: Canada Live website though, if you haven't heard him before.) Rich normally plays a 6 string Ken Lawrence, but I think he pulls out an F for those Orbit room gigs.
The Orbit on Sunday nights is home to a rock/alternative cover band ("Stiffler's Mom") made up of members from Thornley, Big Sugar, and Hawklsey Workman. Mondays, Kevin Breit usually plays, and his Jeff Beck-esque guitar worth is definitely work seeing as well.
I like to frequent a place called the Trane Studio, which usually features more urban and groove oriented jazz. I just checked their schedule, and rinsethealgorithm is playing there March 12. With Rich on bass, Robi Botos on keys, Larnell Lewis on the kit, this jazz fusion band is completley off the hook.
There's always interesting stuff going on at the CBC's Glenn Gould Studio on Front St. If you're not into jazz fusion, The Trews are playing at Glenn Gould on March 12. The acoustics in this sit-down venue are second-to-none.
Church St, mentioned above, is the gay district. I don't know if you knew that, so unless it's your thing, you're probably better off walking Queen West.
