I don't think so. I've been charged $30 + for going over.
its still $25, i go over almost every month.
as for DSL, it really doesnt matter who you choose the lines still belong to Bell, who on occasion will still throttle your speed and is not a dedicated speed, as it states it is "up to" xxMbit.
Cable internet is a bit more reliable in download speeds, as well states it is "up to" xxMbit but more than likely you will get the speed you pay for. But finding one other than Rogers' is tough as they are usually only provided through other TV cable companies. (Cogeco, Aurora Cable, Shaw, etc)
Although if you take a Business Internet connection from Rogers' there is no bw cap, except that you need to take an analogue phone line with the package, like a fax line. The speed is to be 10mbit from what the C/S rep told me when I called in.