Another option is the STM 48 tooth "non-slipper" clutch. Nelly does 'em; I've got one and it's very good. Pro's are: you can use your stock pressure plate, springs, etc; they last longer than the stock clutch; they're quieter; there's no fiddly set-up/maintenance like with a slipper.
I'm yet to be convinced that a slipper is necessary/desirable for primarily road use.
Unless you're a riding god, of course.
In which case, I take it all back.
Oh, the "messing about with clutch pack thickness" mentioned upthread. It's no big deal, really. The worse that can happen is you'll put one of your old "plain" plates in the STM pack.