What should I use to seal a driveway?

If the area is large enough such a road in a development, it would be best to apply a wearing course such as a chip seal or slurry seal.

Example include specifications from the NYSDOT for surface treatments or a slurry seal (International Slurry Surfacing Association (ISSA))

As for a small driveway, if you look on the web you can find information on found several driveway sealers. Some better than others and it is very hard to know the real contents in the container.

A driveway sealer should be mostly asphalt. Many sealers are diluted with extra water, clay or latex to make them fluid, but it is the asphalt that does the job after everything else evaporates away. Having some clay in the sealer gives it viscosity and body. Interestingly, the clay also works as colloidal material to keep the relatively small quantities of asphalt, coal tar, and polymer suspended. Having a polymer is good, but not required. The addition of sand to make them skid-resistant is OK, but on a road, it would be better to apply a proper wearing course (and cheaper too). Some sealers are mostly water and latex; in other words, paint. They should not be used as they will not last and not do the job of waterproofing and reoxidizing the surface.

Resources

Pavement Maintenance workshop manual (pdf)
NYS LTAP Center - Cornell Local Roads Program

Liquid Asphalt Distributors Association of New York

July 2014