Somewhat related subject: How well do USB/serial, USB/parallel and USB/SCSI converters work?
I tried an all-in-one USB-to-legacy-ports adaptor (2 serial, 2 PS/2, 1 parallel, 1 100Mbit ethernet) recently on my laptop and it didn't work at all with my modem or palm cradle, but my laptop wasn't on its approved hardware list, either.
Back on subject:
My idea for the "right" replacement for the floppy is one of the digital camera media. CF or MMC or something. Probably CF. The 8MB cards are going to hold most of your "office-type" files and cost very little ($5 at the corner drugstore), and there's all kinds of scalability in the capacity of storage - 512MB CF cards are out there now, for example, and Microdrives beyond that.
Tough sell, I know, but Sony makes a Memory-stick to floppy adaptor. Something similar could probably be whipped up for "legacy" PCs without CF readers (which aren't that expensive anyway).
They're tiny. Easy to fit in a pocket.
If they get wet, it's not too hard to dry them out without damaging data - I speak from experience here (an oven at around 150 F fixes 'em right up).
One could even make the case that those little solid-state cards are more durable than floppies. All six of the ones I have still work, which is a much higher percentage than the last box of floppy disks I purchased.