Sorry to tell you this. Sept 2005 is considered “near the peak” of the bubble. Prices have only gone down since then.
Currently, your house is probably worth no more than 650k. You may disagree with this, but you will find out once you put your house on the market. In 4S Ranch, prices have already gone down 20%.
Since your down payment is 40k, I think you are now “upside down”. One option for you is to contact the lender & ask them to consider a short sale. Or, you can sell & pay the lender the difference.
In any case, it’s best to sell & cut your loss now, before it gets worse.