My website has also been out for 2.5 years, and there are a million things to do there, too. It rained yesterday, and accordingly I scratched something off my rainy day list: implemented a serial key lookup. It is a minor little snit of a feature that will only be used by probably 5 people, saving me 15 minutes, a month. But when you aggregate those by the dozens, they are really meaningful.
My advice isn't just finish it. It is "just launch it". You'll have all the time in the world to improve the software later -- start getting users and feedback for it today. (Oh, and charge money, starting at launch.)
However, some other things never are truly finished, and you're right, just require launching. I find just launching it is one of the hardest pieces of software development.