We rented a 3-bedroom condo last October (ours slept up to 9 with a pull-out sofa in the living room). It was a great place to relax after a long day with our kids and had a full kitchen and two bathrooms. We ate breakfast there every day, BBQ'd dinner once, and ordered pizza one night.
Since you are going in the SD off-season, you should get a pretty good rate, especially if you're staying for a couple weeks. We found ours through VRBO dot com -- there are lots in SD depending on where you want to stay.
Make sure whatever you rent has a dedicated parking spot or lot if you'll have a car, and if you're paying for an "oceanfront" or "oceanview," ask for pictures of/from the actual unit.
PHXscuba