I keep seeing the argument that non-smokers had the choice to go to a smoke-free restaurant. That, imho, is a stupid stupid argument. A restaurant and a pub are two totally different animals. Many smokers seem to think of this as such that they have lost their right to smoke. They haven't, they have been disbled the ablility to force their smoke on others. You can go outside for a butt. Why is that such a hardship?
As for Tristan's comment about a possible free smoking license, that would not work. If it were the case every single pub would get the license because there would be more business. Even it were not free they'd still all have it. That is also the reason there is virtually no smoke-free pubs without this smoking ban.
In Ontario, they've gone further than to say 'you can't smoke inside.' You also can't smoke within a certain distance of the main entrance (10 feet I think?), you can't smoke under any overhang off of a building (awnings included), and you can't smoke under a patio umbrella if it is touching another patio umbrella, the building or a building overhang.
Point remains; every single pub I know of has an outdoor patio area where you can smoke which is easily accessable. You can still drink out there (Getting service out there is hit or miss, though). I'm personally in favour of the ban; I was too young to go to pubs before the ban was issued so I don't know how bad they were, but I'd been in several places which were smoking establishments and they were quite bad. I'd imagine pubs would be much worse, especially on Friday and Saturday nights.
You haven't lost the liberty to smoke at a pub, you still have it, the door is close by and you can re-enter whenever you like. I've gained the liberty to not have to injest pounds of someone elses cancer to enjoy a beer with some friends, I'm thankful for that.
[EDIT] Oh yes, our ban has been in place for some time now. 4 or 5 years maybe? I forget now. I have to say I love going to pubs where I can taste the beer and the food instead of the tobacco in the air.