Personally, if there's no signficant price/size difference, I'd stick with MicroSD over MiniSD.. N800 has two full size SDHC slots.. N810 has 1 MiniSDHC slot.. based on that trend.. the N900 or whatever might have half a MicroSDHC slot

From looks of things.. the manufacturers seem to first market Full size SD card increases, followed by MicroSD.. and then MiniSD.. and MicroSD vs MiniSD prices are comparable.. Full Size SD cards almost half as much as either..

If you dont mind the esthetics issue.. you could make one of those usb cable adapters and use a flash card reader..