Self-balancing motor sizing and drivers?

I'm starting to plan a self-balancing unicycle and I notice several people that have built them are using 450-500W motors. I'd like to use something a bit more robust, like 750W @ 24v, due to terrain. I'm wondering if that's too much and if the guys that are using 500W are happy with the results? Has anybody tracked their current (amps) usage? My guess is that unless you're going full speed and uphill you'll rarely hit full wattage on your motor except for temporary instances.

One of the challenges I'm finding is that there are motor drivers up to 25A at 24v or 36v that can handle a bit of surge, but then it takes a huge leap to 160A and 400A surge. I don't think I need something that large and expensive, but my electric motor experience is limited.

Could some of you more experienced guys chime in with a bit of advice?

Thanks,
Gyv