My husband and I go to San Diego a lot, it's so much fun. There is so much to do.
Balboa Park is so beautiful to walk around (it is where the zoo is). They also have lots of really fantastic museums and of course the zoo is fantastic. I love the botanical gardens there (small, but really pretty and FREE). You can look into a blaboa park combo pass thing on their website if you are interested in all their museums.
We LOVE Old Town. So much really good food and fun to walk around lots of neat shops and they often have various markets/ arts and craft fairs going on.
Coronado is really pretty, it is fun to walk around the hotel and the little shops down the street. Moo Time creamery is wonderful- their pomegranate chocolate chip ice cream is to die for. Bring a picnic and have lunch on the beach outside the Hotel Del, and then stroll over for ice cream down the street at Moo Time Creamery after.
We love staying over near Mission Beach. We are obsessed with The Mission (the very best breakfast/lunch you will EVER have- the blackberry banana pancakes are like heaven and the mexican hot chocolate is yummo). If you have kids, they have a fun beach there, you can rent bikes, and over by the pier/carnival type area they have one of those wave machines where people can learn to surf in a controlled environment (pay by the hour- it's fun to watch too).
The Wild Animal Park is really great too, but it is a ways out of town (you will drive on a funny road past a ton of Ostrich farms). We had a great time there and ate at Studio Diner on the way back to downtown San Diego. Be aware that because it is more inland it gets a lot hotter there, so go early and be prepared for heat.
The USS Midway is also a fun visit especially if you have kids that are really into ships and airplanes. It is also a pretty area to walk around (FYI you can park at the parking garage at the nearby mall for free).
Have a great time!!
