Define "best value". For a proper brand name light that you won't have to worry about I'd go with Rigid brand lights especially if you will using the Gator in the rain. I've have been using them for 3 or 4 years and have not had a failure or any indication that water is getting inside them. Even the electrical connectors have triple gasket automotive style connectors. On their website they also have very good data about the area their lights illuminate and to what intensity.
There are lots of less expensive clone light options. Many have trouble with the lights fogging or filling with water. When you first get them you can take them apart and silicone caulk the seams and lenses if you want to go cheap and do some work. Also take the specs for many lights with a grain of salt. I've compared some that stated high lumen numbers but were not as bright as my Rigids with a lower rating.