My short answer is YES. For example : strongpassword+game.com compromised,
If I am an attaquer it is really easy for me to understand the pattern you used and try it on other websites. For example strongpassword+paypal.com
Argh!....
In order to fix this I personally use:
hash ( strongpassword+game.com )
hash ( strongpassword+paypal.com )
Using mathematical properties about hash (I use sha1), knowing first password it is difficult to discover strongpassword and the second password.
If you wand more details, I made a blog entry about password security which answer exactly to your question:
http://yannesposito.com/Scratch/en/blog/Password-Management/
I also made some tools to make it easier to manages all my password, because you need to be able to change a compromised password, remember max length of a password, etc...
