You’ll be able to ride from your doorstep anywhere you live in Brighton, there are cheeky green lanes up to the Downs all over the place, i don’t know anyone that lives in the town who drives the couple of miles up to the Downs
you haven’t mentioned a budget and it depends on what you mean by ‘best’, if you want nightlife and pubs and cafes then the middle of town is obviously ‘best’, although you’ll pay a premium, obviously, but saying that you can get to the centre of town within 20 mins on a bike from the far flung outskirts
if by ‘best’ you mean instant ride access then maybe the suburbs are for you, i can be off-road within three minutes and can do a ride that will rival anywhere in the UK in less time than it takes to drive to Wales