I'll toss in one that hasn't been mentioned. I use CassetteHouse now more often since TT stopped selling media. They do cost more, but they also have sales regularly which is when I stock up (I usually buy in lots of 100 or 50 in order to not have to rush out to buy tapes). They still have Fuji tape which is what is in their MasterDAT DATs, and they also sell 94 minute unlabeled Fuji tape -- cheap, which comes in handy for local bands.
Wayne