Not sure what itd be worth to them... If its his fault- his insurance should have to replace yours with equal or better. Was he insured? If yours is totaled, don't sign anything until you're sure it's a fair deal. A car will usually be given market value. If you got photos of the accident... Do you have photos of it before the wreck? I'd go and find all the cars that are in the same condition as yours was, the ones for sale for the most, and prepare packet so that you're ready to argue what your car is worth should they not offer what you want. If it was me... I'd be prepared to let them know I'm willing to hire a lawyer if needed. They usually want to give you a depreciated value... You can look at similars for an idea what they'd pay. But, honestly- I'd argue for more for the inconvieniance. Plus all costs to get the car legal- tax, tag, title, dealer fees.
Edit: I didn't realize this was the st forum.. Duh, ST.