Push hard for them to total it, and be sure you get equivalent to the cost of an exact replacement in today's market.
Hopefully you have an RCE (replacement cost endorsement) on the policy.
If they insist on repairing it, request a diminished value settlement as well. If it's repaired, when the time comes to sell it you will never get anything CLOSE to the value of the same unit that's never been damaged. Unfortunately, if this be the case, you'll probably need an attorney to go to bat for you (especially with Geico -- I've had experience with them in the past).
Best of luck to you, but lastly, be sure you are 100% happy with your settlement before you sign any kind of release.