This is some good advice:
You can negotiate how much they give you. I did it with my fiancee's Jeep, although the Ins. Co. wasn't too happy about it. We got fair market value for the vehicle. If they're lowballing you, then fight it. However, realize that your car may not be worth as much as you think that it might be. Check fair market value through the methods listed above.
www.kbb.com is a good resource.
Also, we got money for a rental car, although it was only about $30 per day. Altogether it turned out pretty well for us. To "replace" the Jeep, we purchaced an e36 325i.