Check out the early sport bikes, if you can find a clean one they could be a blast and rather unique. Sort of like a early 911. Sure the newest ones are better/faster but does that really matter. Check out this old 1985 VFR 1000 Gear driven cams, the best of it's day anti dive forks and 16" wheels for quick steering. I think they were just cracking past 150 mph back then.
Nice and for only a few $
http://www.walnecks.com/search/detail.cfm?ID=75884766