Okay, maybe that's going a little far, but BMV is a very good store. Everyone seems to agree, so I'm just throwing my additional two cents onto the top of the pile.
One great thing about it is that they sell new books at a major discount. Perfect remainders. Stuff they're still selling at Chapters for, say, $25, you can often get brand new at BMV for $6.99. I recently bought copies of a variety of David Sedaris books and two Chuck Klostermans this way.
Another great thing is the abundance of used texts. Aisle after aisle of used books, all in great condition, selling for at least 75% less than what you'd pay most elsewhere. I've been known to come away with too many to haul home in one go.
They have a great children's section upstairs, and albums in the basement. Don't shun the bins out front either. Those dollar books and CDs (often sold 3 for $10) are worth a look.
My only real criticisms are as follows: they don't have everything and if you're looking for something specific, you might be out of luck. Specific texts can also be a bit difficult to find because they have smallish sections for things like Canadiana. So books aren't always where you expect them to be unless you know a fair bit about authors.
That said, just wander the store for a bit and you'll soon figure it out. (They also sell gift cards and have a buying desk in the back corner if you're looking to sell.)
One final word of advice, though: if you are perusing the bins out front, beware harassment from nutbars. I have regularly been accosted by weirdos while trying to peep some books. That's not BMV's fault, but it is something to look out for.
471 Bloor Street W
Toronto, ON M5S 1X9
*Photo by Sanja Gjenero from Stock Xchng.