In light of yesterday's Yahoo password breach and new news now that NVIDIA and Phandroid forums have been hacked too, you might want to check Should I Change My Password? just to be on the safe side. The site checks your email against any recent hack.
We've mentioned Should I Change My Password? last year, but since then the site has added a new feature that emails you when there are new security breaches so you can check again.
Avalanche Technology Group, which runs the site, state they do not record your email address unless you select to be notified about new compromises and in those cases, the email is stored with MailChimp and never sold or shared (see their FAQs here).
They have a long list of sources for the hacked databases, including compromises that haven't been covered in the media.