Montreal--good for shopping?

Hi,

We are planning a trip to Montreal, and we are concerned about the size of old town. Will there be enough to do over a 3 or 4 day trip? We went to Quebec City last year and we were shocked at how small the old city was. We were bored after 2 days! I realize that Montreal is a large city but we are not into partying and don't care about the bar's, etc. We are more interested in shops and cafes. Any advice? Will it be just like Quebec City? Should we pick somewhere else???