It's fine to settle with the insurance company for the bike and any immediate medical bills. If the insurance company offers less than you think you should be getting, then you need to do some homework and prove that the bike was worth what you are trying to get from them. I'd try to get the full replacement cost of the gear, since you are going to have to buy new gear to replace what you lost. This isn't so much like haggling over a new car or bike as it is coming to an agreement on what it will cost to replace everything you lost and make you whole again. If they are lowballing you, then you need to be able to provide them with proof that their offer is too low. In addition to the value of the bike before the accident, you should be fully reimbursed for any towing, doctor's visits (even if you are just getting checked out and the doctor finds nothing seriously wrong), and anything else that you have no choice but to buy new replacements for.
Don't sign anything that releases them from future medical payments, since you don't know at the moment what, if any, future medical costs you might incur. If they are hard-nosed about getting you to release them, then let them know that you will have to talk to a lawyer. Then go talk to a lawyer.
Finally, don't threaten the insurance company with anything you are not prepared to follow through with. Chances are, they will call your bluff if you threaten to take them to court right off the bat, so I'd just let them know that you're willing to consult a lawyer if you aren't satisfied. Then consult one if you aren't satisfied.
Don't sign anything that releases them from future medical payments, since you don't know at the moment what, if any, future medical costs you might incur. If they are hard-nosed about getting you to release them, then let them know that you will have to talk to a lawyer. Then go talk to a lawyer.
Finally, don't threaten the insurance company with anything you are not prepared to follow through with. Chances are, they will call your bluff if you threaten to take them to court right off the bat, so I'd just let them know that you're willing to consult a lawyer if you aren't satisfied. Then consult one if you aren't satisfied.