You should generally not use the same password more than once (on accounts you really care about) - it's bad practice. I say this because - very frequently - databases are "hacked" and entire password databases stolen. In addition, to make the situation worse, sometimes these are not properly secured (or not even encrypted at all) - some are intentionally insecure. Even more frightening is the fact that such events are not always detected - and if they are they are not always reported to the public.

You are smart to be concerned about this - however I'd encourage not having a regular password for the reasons above. Having a password that is hard to crack (ie 'high-entropy') is also advisable.