There is a whole world of conventional stuff you can still get into!
Press the [SRCH] button. Then press it again. And again. This will toggle you through most of the more popular conventional stuff. This is just a search - hardcore conventional users will want to program the good stuff into scanlists.
In San Diego - I think the Marine channels would be of major interest.
Then again, as you step through all the [SRCH] options, you'll find Railroad, Aircraft (both civil AND military-air) Ham-Radio (amateur radio), and CB - although for CB, you'll want a better low-band antenna. How about GMRS/MURS?
You are well set up for the Miramar Airshow this Sep 30 - Oct 2!
Welcome to MCAS Miramar Air Show
You should be able to hear some interesting stuff even if you don't actually attend!
Thanks to airnav.com I found some interesting Miramar freqs you may want to check out now:
135.200 AM
298.925 AM
340.200 AM
These are just 3 Miramar tower freqs - if you don't hear the tower, you should hear the planes at times.
How about San Diego International Tower:
118.300 AM
338.225 AM
The best bet for getting into aircraft is by visiting the forum for it, and using things like airnav.com to get frequencies in use faster than just letting the 106/500 do it's own search. Communications are somewhat short, so they are easy to miss with plain old searching if you don't do it long enough. Don't forget that aircraft are mostly AM, so you'll want to doublecheck that modulation format in the "expert menu".
Obviously you see that my conventional scanning is for the most part aeronautical.
All the others have their forums here too with other frequency references. Just stop in and say hello!