Hey Red,
I'd tend to agree with the others that your A1200 set-up is pretty much ideal for a bit of retro dabbling. The only reason I can see for getting USB is for easy data transfer.
Personally, while I love emulation for letting me have the powerful Miggy I could never afford back in the day, there's something to be said for the real deal when it comes to having a bit of 'old skool' fun - the tactile experience of a real Amiga keyboard, warming your feet on the PSU, the buzz of the floppy drive... can't be emulated.
Once I finally get a bigger place, the first thing I'm going to do is put together a similar spec A1200 setup.
