Personally, in terms of the "memos" (by definition short, a sort of "sticky") I use the native app "Notes". It is not synchronized but it is possible to send the memo by mail ... Practice.
For the "Notes" as such, I use a lot of happiness with Simplenote (sync on the web). And I must say, for simplicity and ease, I also Simplenote for my various lists: shopping lists, books, DVDs, etc..
Well, apart from my things to do, everything is concentrated in one place, I can view, edit, etc.. both on my pc on my Palm Pre +.
That, hopefully get you a little help ...