Birthday Weekend Ideas?

My 25th birthday is in the upcoming weeks and my girlfriend and I are looking to take a weekend getaway but are having trouble deciding on where.

I definitely want to be somewhere beautiful and exciting with lots to do, preferably within 4 hours driving distance of SD. We're into hiking, swimming, beaches, bars and restaurants and general nightlife fun. This is extremely broad but I hope you beautiful San Diegans can share some good experiences or recommendations for a really fun weekend! (If there's a place to go waterfall/bridge jumping, let me in on it!!!)