The best concerts/shows I've attended to this point (in no particular order) are:
Kraftwerk (they're freakin' Kraftwerk - that says enough!)
The Ramones (multiple times - best show I went to was in 1990)
Depeche Mode (Violator tour - Nitzer Ebb and The Jesus and Mary Chain opened!)
The Viletones (reunion show - seminal Canadian punk band)
Lollapalooza 92 (how about RHCP, Ministry, Soundgarden AND Pearl Jam among others on one bill!)
The Specials (another amazing reunion show - ska shows are the best!)
The Cramps (my hearing isn't what it was 15 years ago thanks to that show!)
The Doors (with the amazing Ian Astbury as front man - if anyone HAS to step in for Jim Morrison)
Queens of the Stone Age (because Josh Homme is just HOT, and The Distillers opened, which was alright!
Matisyahu (a full-on hasidic Jewish guy who plays reggae... with a twist!)
Strangely enough, some of my favourite studio bands are completely retarded live - Oasis comes to mind immediately.
I've also had to opportunity of meeting a few well-known Canadian musicians - I guess just being in the right place at the right time.