The 16MB cards will cost about the same as an 8MB PS2 memory card. If the prices come down even more (and they will) I may consider a 64MB bad boy.
So far the prices are as follows:
Panasonic's 64MB SD Memory Card -- $99.95
Panasonic's 32MB SD Memory Card -- $59.95
Panasonic's 16MB SD Memory Card -- $39.95
no price for the 8MB version but sources indicate it will be less than $30
Panasonic plans on having SD cards around the 4GB marker in about 3 more years!!!