I'm down to 52MB left on my Fuze v2 4GB after adding about 20 tracks from the Orange Box soundtrack, and I don't know what size microSD/microSDHC card to get to expand it.
Rockbox is installed on it, but I'm not worried. It seems to support microSD/microSDHC according to the debug screens.
I plan on replacing it around the course of 6 months since dead pixels are starting to appear around the edges of the screen. I also plan for the replacement to also support microSD/microSDHC.
Needs to be < $15 too.
8GB or 16GB microSD/microSDHC card?