Thanks for all the suggestions!
I'm currently running Atari800MacX, which is a great emulator, but I'd love to get into using the real hardware.
In answer to the above question "what do I want to do with my collection", I want to collect and use them... and potentially look at the customisation scene as well. I have some very fond memories of playing games on the old Ataris when I was little and it'd be great fun to recapture that.
The SIO2PC/OSX thing looks great. Does it sit externally or do you need to mount it inside the hardware? And am I right in thinking you can use it to boot the Atari from a disk image on a PC/Mac? (I'm a Mac user by the way, but can boot into Windows if necessary)
I actually would like a disk drive at some point because - it sounds bizarre - I miss the sound of it. The one thing the emulators don't seem to do right is the "loading sound" when booting from disk - I used to love the sound from the computer and the snark-snark-whirr of the 810 and later 1050 while you were loading something. That's one thing that seems to be missing from the emulation scene at the moment. Sure, loading a disk image quickly is efficient... but for the authentic experience? Gimme that BLBLBLBLBLBLBLBLBLBLBLBL! (pause, zurbit) BLBLBLBLBLBLBLBLBLBL! (pause, snark) BLBLBLBLBLBLBLBL! (snark) any day.
Also noticed you mentioned Wico sticks above. We had a Wico stick, it was great and very "arcadey"... but the fire buttons died on it relatively quickly, from what I recall. We got through one hell of a lot of joysticks over the years.