The smallest package I would ever consider practical for all purposes is definitely the Glock 19. In "normal" form, it holds 15 rds of 9mm, has a 4" barrel and is considered a "compact" pistol. It is simple to use, take apart. The manual of arms is dead easy ( just keep your finger and clothes off the trigger till ready to shoot) and it goes bang everytime. It is lightweight ( the P7 is all metal and butt heavy) and a perfect compromise between a full size gun like a 1911 or even the G17, and the tiny pocket pistol, sub-compact class like the G27 gdawg mentioned. The small guns are hard to shoot, hard to hold and don't even think about getting one in .40 or .45 unless you practice a lot.
I've owned both the G19 and the P7M8 since the late 80s. I still have the G19 and it's the pistol I shoot the most.
The whole point is moot in Canada anyways since 1995 as most people can't have anything shorter than a 4.2" barrel and 10rd mags.
Someone mentioned a Makarov. Ugly with the long nose but a surprisingly good gun! Very accurate and the 9x18 round doesn't kick much from such a compact gun. The trigger is creepy but workable. If you get one, find the Fabarms kit to convert it from a heel mag release and also get the Spetnaz holster. You'll know why when you get one!