I have a bike bell on my pink city bike. It's a metal one so it really has a very traditional bike bell sound. I use it mostly for fun, because it makes me happy to hear it.

See its sister bells here:
http://www.dringdring.ca/catalogue%20sonnettes.html
(Mine is the one with the cat but I also love the pink candy, goes well with a cycling top from Shebeest 2 years ago)