Unfortunately because your SE isn't one with a high density (1.4MB) drive, it won't work. All USB floppy drives only support the 1.4MB format - not 800K. To further complicate things, Apple removed support for your SE's file system in 10.6, so regardless you'd need to use 10.5 or older.What about a floppy-drive for Mac OS X?
But ftp will be just fine. In fact, that's a good way to transfer files from OS X to your SE. The trouble is getting the System, ethernet drivers, TCP/IP, and an FTP onto the SE to begin with.I do not recommend buying an ethernet card to connect your SE to internet. It will be very slow.
Direct Ethernet to the SE would be the fastest method. There is no faster connection available. And it would be a single-step, direct from OS X machine to SE. (As dmr727 mentions, FTP works just fine.)I do not recommend buying an ethernet card to connect your SE to internet. It will be very slow. And a floppy drive for Mac OS X will be expensive, probably more than a used beige powermac...
Enjoy your vintage mac, I am like you. I like to spend time with them