I lived my 20s in San Diego. I just moved away two years ago, not because I didn't like the city, but to be closer to family.

I think Pacific Beach would be perfect for you. Your commute would be going against traffic for the most part (depending on your start and end points, you may not even have to get on the 5), and PB has everything you ask for.

Mission Beach and Ocean Beach also have a hip bar/restaurant scene, but are a little grittier than PB. Another beach community you might like is Encinitas, but it's a good 20-30 minute drive north on the 5.

Downtown SD is constantly growing and changing. I just went back to visit a few weeks ago and I was amazed at all the new construction. If you like the urban scene it's a great place to be, especially around the Gaslamp Quarter.

Good luck.