The Mozilla foundation kicked off a competition for Firefox extension developers (to be). So if you have an idea for an new extension or upgrade your existing one, take a look at the extend firefox contest.
Do so before January 6, 2006. And it’s not for eternal fame only. There are some nice prices to be had.
PS: I’d like to have a GMail notifier that checks multiple accounts, maybe throw in a POP3 checker for generic mail accounts… It’s just an idea. 🙂
Update: Asa is pointing to the “New features for extension developers in Firefox 1.5” by Jesse Ruderman. Which should provide enough idea’s for 1.5 extensions.