The RPG city map generator is indeed rather spiffy. If nothing else it can give you a good starting point.

If you want to produce a city of your own design rather than a random one, you can still use the generator to produce large fields of buildings which you can cut and paste as need to fill your own city layouts. Just create a biggish city with a few roads, loasds of buildings and nothing else and you'll get lots of bits to play with. Takes a little longer than using a random city, but it's still much quicker than drawing it all individually.

After that of course you can hand draw any extras or special buildings that you want.