I agree with Jim and Mystic, great advice for you. The plan I have always used with my clients is simple, if you have a budget then you should do PPC ads (very targeted though, no wide terms like California Real Estate, but more on the line of "Cupertino Real Estate" or "Cupertino Homes For Sale" as an example).
What you will learn are the keywords and phrases that convert best. This will give you insight into where your SEO efforts need to be focused. Then you can build out pages for those specific terms and you already know they draw in the most interested buyers.
One tip though, in PPC (and I have managed $500K monthly PPC budgets) it is extremely important that you have continuity in your ads. So if you bid on the term "Cupertino Homes For Sale" then you will want the display URL to be something like: www.myrealtorsite.com/cupertino_homes (not real used only to illustrate), and when they get to the page, the main headline says "Cupertino Homes For Sale" and then the content on the page are your Cupertino listings.
I too often see clients sending clicks to "silver bullet" landing pages that only increase the likelihood that they will leave the party and you will not have even gotten so much as a handshake. Be aware also, that doing this sort of "deep linking" will also raise your relevancy scores which will in turn lower your average bid cost. Initially you will pay higher per click costs because Google needs to get comfortable with you and charging you more at first is their way of checking to make sure you are serious and that you will provide good relevant content once the user clicks on your ads.
Last thing to keep in mind, all traffic to your site has a cost. Make sure that you do not waste your money, get their email address by offering more than anyone else (like a free report on Cupertino Real Estate Trends for 2008 and 2009). Make it personal and engage the potential client with reasons to buy from you as opposed to someone else (i.e. testimonials, both written and video, logos from your various organizations and the BBB, as well as resources that they can use to make better decisions).
Hope this helps in shaping your marketing plan.
Cheers,
Jim Lillig