as mentioned the Buttertubbs pass is awesome as is the road from the Ribble viaduct to Hawes plenty of opportunity to dice with the bikes
both the above are great and I'm sure all those mentioned in previous posts have something to recommend them but my absolute fav is the Mountain section of the TT course on the Isle of Man, approx 9 miles from Ramsey to Douglas well surfaced (it as to be it's part of the race track) well sighted (mostly), good mix of medium fast, fast and OMG fast, and best of all no speed limits, motoring nirvana
both the above are great and I'm sure all those mentioned in previous posts have something to recommend them but my absolute fav is the Mountain section of the TT course on the Isle of Man, approx 9 miles from Ramsey to Douglas well surfaced (it as to be it's part of the race track) well sighted (mostly), good mix of medium fast, fast and OMG fast, and best of all no speed limits, motoring nirvana