I'll be on a 2-weeks biz trip in Ontario, CA, and I was wondering if anyone from either Los Angeles or San Francisco could recommend me some good comic stores where I can buy vintage comics, as there's a possibility to either visit SF or LA during the weekend.

In particular I'm looking into the Transformers Marvel series and the IDW/Dreamwave storylines. Buying them online is really prohibitive due to shipping costs and they are usually delivered to me completely damaged due to poor handling of the postman trying to fit them in the slot of a 4" mailbox