When you're trying to light a parking lot you're going to need some seriously high powered bulbs for the job. You're lighting an incredibly large area, with the one positive being that it's mostly wide open spaces. The goal is to keep the entire area lit up, leaving as little room for dark spaces as possible. If you're running a store this is mandatory because it means a bit more safety for your customer base. The most popular lighting for a parking lot is typically going with large area lights. These give you the choice of CFL style bulbs, Metal Halide, and the increasingly popular LED light option. As long as you're going an outdoor solar lighting any option is great, but you're going to want to lean more toward the LED in most cases as it provides amazing light while burning less energy, and lasting longer than your other choices. While CFL is good, they just can't compete with the luminosity put out by an LED bulb. When combined with a solar setup you're looking at the absolute best energy option available.
Lighting a park is another interesting scenario as it requires a bit more intimate lighting than what you would use for a parking lot. You're going to want to have lighting closer to ground level, something that's going to be used to light up a walkway instead of looking to light the entire area around said park. Once again you have to select LED versus CFL and Metal Halide light bull options, you'll have to look decide which one works best for your location. The fun part of park lighting is less in the bulb style and more in selecting the appearance you want for your lights. Many locations these days are going for the more classic column with a canister on top, a touch of old world style with modern LED bulbs. It gives you a great blend of past and present, lighting the way toward the future. No matter what decision you make, as long as you're focused on going with solar lighting solutions, you'll be coming out as the winner in your project. With the breakthroughs in solar cell production in recent years it's bound to get even better as time ticks forward, keep your finger on the pulse and all will go well.