I use a different pass for basically everything. The strength depends on how much I care about my account at the service. I've been known to do stuff like "<servicename>sucks" when I really don't care about it. Everything somewhat important is longish, with some capitals/numbers/special chars.

I have FF remember all of my passes basically (on my own computer with a good password on it.) I make fairly heavy use of "forgot pass" functions to make up for forgetting some passes.