Notepad++ v5.1 fixed bugs and added features (from v5.0.3) :
1. Make Notepad++ Unicode-compliant application(Unicode path supported).
2. Fix crash issue due to the incoherent modification/creation date.
3. Enhance Find in files feature : launch in thread, stop as wish.
4. Add find/replace dialog memorize capacity.
You can find the full list on the change.log after installation.