The Manchester Grand Hyatt San Diego was one of the “official” hotels of the conference I was attending and is only a few blocks from the Convention Center. I booked a Double Bed at Costco rates as it was the best I could find; each night just under $300. There were two large conferences in town (one at the hotel), so I am guessing you could find some better rates if you go when there isn’t a conference in town. It is the largest hotel in San Diego (with 1,625 rooms).
The Manchester Grand Hyatt San Diego is located on the waterfront just south west of the downtown core. It is about 10 minutes from the airport and you can walk to Petco Park, the Convention Center, Gaslamp, and downtown. There are a bunch of restaurants just across the street. Across the street there is also a light rail stop.