I believe that we will indeed see continued depreciation in the high end market. The question is how much. My wife and I like Birdrock a lot and back in 02 we toyed with the idea of moving there and regretfully did not.
To be honest I think you are overpaying for the home however you are purchasing smack in the middle of a spring rally. if you are intending on holding for 10 years like you implied I tend to think that you will have an opportunity to not be underwater at some point in that timespan. If financial considerations are the only factor then it is a no brainer, do not buy. Only you can measure the decision of lifestyle verses financials. You already mentioned that your current rent is higher then what this payment will be. Did you include property tax as well?
I will tell you that Birdrock is a great place to live. I will also tell you that other opportunities will arise but you will have to be patient. There are always more homes that come along, however the good ones seem to not come along to often. If you are trying to guess what the bottom will be for la jolla and Birdrock…hard to say…right now it is seeing more demand then in the past year or two but I think another 10 to 20 percent is not impossible iF things really crap out.