It depends what province you're returning home to. I brought home 2 extra bottles from a visit to France recently. I declared that I had extra wine at customs (and on the form) and was sent to the cashier to pay - it was not really any hassle at all.

HOWEVER, the customs agent almost breathed a sigh of relief when she saw I was from Ontario. She said the Quebec duties are "very high" - when I asked, she said it works out to about 218% on wine. (218% of what you paid for it). For Ontario, it's 39.6% of the declared value for wine, 59.9% for spirits, and $0.676/litre for beer. Then there's GST, PST. That's for the stuff that's with you & your luggage, if you send it separately it's much higher (around 110% for wine, for instance). I "chose" the cheaper bottles to pay the duty (with receipts), and they had no problem with that.

Note these numbers/ amounts are all from the LCBO info-line, I emailed them after the fact. So I would check with your provincial liquor board for exact information. Hope this helps!