I've been meaning to get a USB Thumb drive for a while now and have been managing on my PDA plugged in transferring via that. Although that means that you need to install ActiveSync on each machine you plug into, which is not always practical.
I went on ebay and found a USB THumb drive card reader. IT reads SD, MMC and RS-MMC. I've got an adapter for my 2Gg MiniSD cards that fit my O2 Atom. So now I've got 2x2Gb storage...for AUD$8...that's a bargain and at a fast transfer rate too!
It's only the second thing I've bought on Ebay and so far I'm really impressed.