Joe, before you do anything about that cracked floor -- test for radon first. Better yet, have a professional make the test for you. Another reason for contacting a professional: you may need to install a system to exhaust the vapors if the radon is present in a dangerous concentration. The concentration of radon should be checked both before and after the concrete is sealed. Sealing the cracks in the floor of your basement may be all that you need to do -- then again, maybe more work will be needed. Hopefully you will not have to install the exhaust system we mentioned. In any event, use a polyurethane concrete caulk. Remember: you are dealing with simple, old-fashioned gas vapors. There doesn't seem to be much pressure associated with radon vapors, so pretty much any concrete caulk will do. We have recommended the type that bonds the best and that holds up the longest.
Inasmuch as snow shovels are concerned we suggest that you contact someone at your local tool rental store for unbiased advice. The brand that they buy will be the one that probably holds up the best and will more than likely have been purchased locally, and therefore, should be readily available to you as well.