If you have never visited I would suggest a trip to Las Vegas.
San Diego is lovely and all(and I do like to take the occassional weekend there)-but a bit of a yawn.
Las Vegas is unlike any other city you have experienced.
You will love it or hate it.But you will not forget it.
Since the pound is so valuable right now you should splurge on one of the great places on the strip.
More advice on that in the Las Vegas forum.

And no reason you cannot do both=I love LA But 7 days is too much.