I can strongly recommend Notation Velocity for these use cases (or rather, nvALT[1]). It's perfect for creating massive amounts of short snippets, stores them as plain text files, has a pretty novel full-text search and navigation interface (using basic vim bindings even!), and a whole bunch of other features that doesn't clutter things up (markdown, for one, as well as basic wiki-like linking between notes).
My current NV 'library' contains more than 1600 files, ranging from command snippets to journal entries to on-the-go wifi passwords to project meeting notes and lists and whatnot. On top of that I have two separate libraries that contain more sensitive data.
Oh, and using Dropbox or the like, you can sync the notes between computers, and with SimpleNote (as well as some other apps) you can access all of it on your mobile device.
[1]: http://brettterpstra.com/projects/nvalt/