In a perfect world with nice clean fuels, running the lowest octane you can without detonation is ideal. It has the most power. Higher octane is generally a higher flash point and less energy per gallon. In reality it isnt a bad idea to run a little higher octane fuel just because it is generally a little higher quality. You could always go to Alky, its nice and cheap compared to race gas or premium. Not real practical, but it is nice having freezing cold intakes and a warm cylinder and pipes instead of burning hot parts.
'93 Banshee, Passion, FAST, Cascade, Noss, CP Ind, JJ&A, DMR, Skat Trak, LSR
'88 350r, CT, LSR, ESR, Quad Tech, Skat Trak, TCS, Works, Maier, HiPer
'09 YFZ450r, Stolen
'09 KTM 505 SX