I recommend Sandisk since ive tried kingston, ATP and other brands on mutiple S60 phones from 3650,6600,6620,6670,n80,e61,n73
They seem to have the least amount of issues. I dont mean big problems but small things like theme will sometimes go back to the default same as with ringtones on the card. Reason from what im told is the info dosent get read fast enough so the phone goes to the default.
You can get sandisks pretty cheap off this seller and they are OEM(the ones he says are Sandisk that is).
http://cgi.ebay.ca/NEW-2GB-SANDISK-MINI-SD-MINISD-MEMORY-CARD-2-G-GB-IN-UK_W0QQitemZ270111289061QQihZ017QQcategoryZ18871QQtcZphotoQQcmdZViewItem