You can store the .kdb file on a shared dropbox folder. I know it's not as safe as keeping separate .kdb files (theoretically your dropbox folder can be hacked, but they still would need your master password), but to me it's a sacrifice in the name of convenience. Pro tip: you can even sync to the minikeepass app on your iphone. It's great having all your passwords always with you!

Dropbox of course. There are some good mobile clients (i use KyPass on iPhone), so you can have your passwords literally everywhere.