Barnies right, for your purpose, get the cheapest 1 gig SD card that can find.
SD cards have transfer speeds associated to them.
Unlike say cameras that need to write on the card on every pic snapped, for your purpose- you'll only have to read off the card. Transfer rates will not influence read speed.
A cheap 1 gig SD card (make sure you don't buy a mini, ot micro SD card) in Toronto will run me under $20.
As for SD vs MMC, you will not notice the difference for your application.
You may have more use for an SD card in other applications.
Good luck.
R B