I was there a couple months ago for San Diego Beer Week and my favorite place in the Gaslamp District was the Tipsy Crow on the corner of 5th Ave and F Street. They had a really nice craft beer selection and very friendly, knowledgeable staff. We stopped in for a quick drink and to check out the hemp ale on cask that they were about to tap and ended up staying for at least 2 hours.
Right down the street is Analog Bar, a 70's-80's themed bar with a pseudo lounge feel. They don't have the best craft beer selection but do have some awesome happy hour specials (especially on Tuesday I believe) and delicious tater tot appetizers.
Outside of Gaslamp, you really should check out Toronado on 30th St. for possibly the best craft beer list in SD, the Blind Lady Ale House for another awesome beer list, and Stone's brewery (about 45 min north of town in Escondido) as it is pretty amazing. I would also suggest Port Brewing/Lost Abbey which are both in the same location in San Marcos. While you're there you can also visit Churchill's Pub for yet more great craft beer.
One more thing. Call Lucha Libre and reserve the Champion's Table for lunch or dinner some day. Go in, skip the line, get treated better than everyone else in the joint, and enjoy some amazing burritos while having fun basking in your own awesomeness.
Have an awesome trip!