What I like best about Brighton is the music. From the Freebutt to the Brighton Centre there is something to cater for most peoples musical tastes. Of course, the further left your tastes are, the trickier things are to find.
To begin with there are a couple of good live nights out there. The Safehouse is a free jazz/improv night at the Open House pub Brighton. 2008 looks a good year with gigs by Evan Parker and Steve Beresford lined up. Instrumentality at the Fortune of War looks like an experimental electronica/techno night with lots of local acts playing live. Finally is Spirit Of Gravity who have been around for years. They are an electroniuca collective with their own record label.
New Music Brighton.
One of my favourite record shops is Edgeworld Records. It is above a clothes shop in Kensington Gardens in Brighton and stocks all he records the other shops won't touch. They probably sell records by DJ Scotchegg, Fujiya & Miyagi and The Polly Shang Kuan Band.
Finally there is a local blog that covers all things musically weird. It is called 20 Jazz Funk Greats after the Throbbing Gristle album.