I sprayed my Raleigh with Rustoleum rattlecan black. It's very soft and chips and scratches easily. On the upside though, touchup is easy -- just spritz with a little more paint. If you're going for the "semi-respectable beater" look, I recommend it.
On thing that I have heard (but have not tried), is that automotive paint stores can mix proper automotive paint and put it in a rattle can for you. I've heard that they don't like to do it because it's a PITA, but apparently many can. Most auto paint is catalysed -- that means it will harden in the can after some short (measured in hours) time, so the technique would be: 1. Strip and prep bike 2. Prime bike 3. Go to store and get paint made 4. Quick-like-a-bunny rush home and paint bike.
There are also little spray setups in which you can mix your paint, dump it in, charge it up (using something similar to a CO2 cartridge), and spray. Auto paint stores have them. I forget what they're called....