Sorry, Drew - here's your requested info -
OK, in brief - for anyone else who travels out here. La Jolla is a great place for shore dives - there is plenty of macro at La Jolla Shores (pretty protected, but definitely a classic surf entry on some days - I have sacrificed fins on 2 occasions, and probably only 2 because I tend to get wussy and call dives if the surf is as tall as my head - you want to have everything clipped to you!) and WA (lots of kelp!) at La Jolla Cove - less protected from surge, but generally an easy entry. In the summer, the drawback is PARKING. I warned Alex that on the Saturday of Labor Day weekend, we will need to be parked at the crack of dawn, and I can guarantee there will still be some ridiculous clown pulling up to ask if we are leaving when we are geared up and heading into the water. (I have, indeed, said YES before, enjoying the look of confusion on aforementioned clown's mug as I walk away and leave my car parked and locked...yes, I am going to hell.) If you want to shore dive, especially at La Jolla Shores, it's probably best to get someone who's been there before to take you.
Boats are aplenty - our fave is Marissa Dive Charters, the Lois Ann is also pretty nice. They run to Point Loma - great macro there, kelp with structure - meaning nudibranchs everywhere, saw a mola there last Sunday - the drawback is water temps slightly colder than the shore dives or Los Coronados. Also - Wreck Alley (Yukon, Ruby E, NOSC tower) which have a mix of macro and WA, and they'll run to less-known wrecks like the Hogan or the P-38 if you plan ahead and they know your abilities. I agree with James that Los Coronados can also be great, especially for the sea lions - it is a long run out, though, and the only boat headed there that Saturday is chock-a-block. (Same theme as before - if you come in the summer - book/plan early).
Water temps - I am a fan of my drysuit, year-round, though there are lots of wetsuit divers in these parts. I think they're all crazy, but I'm a girl, and I get cold. Temps can range from the upper 40's in the winter to the 60's in summer depending on site and depth - and the whim of the gods.
If anyone comes for longer than a day, Scott G books some awesome day trips up LA-way directed at camera junkies - Oil Rigs, Catalina - I have been on two in the past few months and am booked on another in the fall, even though it means I have to be on the road at 4:15 am and then hang out with Scott all day (kidding - love ya, Sko-T!!). Highly recommend them!!
OK, must turn off my computer and get to work. Hope this helps anyone headed out this way...