Instead of getting a high density floppy for the A2000(s), I'd recommend a
Catweasel card. The Mk2 ZII comes with an integrated Buddha three channel (six drive) IDE controller (which may come in handy if you have any spare IDE drives) and the Mk3 'Flipper' is both a Zorro card and a PCI card (there are two edge connectors on either side of the card, hence 'Flipper'). Both allow you to use 'standard' IBM PC HD floppy drives as Amiga HD floppy drives...
I love my Mk2!
BTW Dave, are you getting a X-Surf 2 or the original from Software Hut? The X-Surf 2 comes with PPoE drivers for the Genesis stack included with OS 3.9. Who know, you might be able to tack a Catweasel onto your order :-D.