When you've still got many miles ahead and are looking for a boost, but not in the mood for coffee or cola, you're in luck. More and more energy drinks are filling the shelves at stores like TravelCenters of America, offering the caffeine buzz of that traditional cup o' joe, but wrapped in herbal and other ingredients.

Many of these drinks come in the slender can size made popular by the original energy drink Red Bull. Each has its own taste, from sweet to juice-like to medicinal.

Besides caffeine, almost all contain taurine, an amino acid that is depleted from the body in times of stress and physical exertion. Many also contain ginseng, an herb that's supposed to improve concentration and your body's reaction to stress. None of the health claims made by these drinks have been studied in depth, though, so it's most likely the caffeine accounts for the majority of the energy boost. Additional ingredients simply distinguish the beverage from soda.

We popped the tops on several of the more popular energy drinks out there. What follows is a subjective review of their taste.

Key:

Rush! Energy Lite
Made By: Monarch Beverage Company
Size: 8.3 oz. and 16 oz.
Color: Cherry red
Taste: Very bubbly, very sweet, fruit punch flavor, reminiscent of Hi-C Special Ingredients: Taurine and D-Glucuronolactone, a natural substance that is supposed to help remove toxins from the body
Caffeine content:
Claims: Increases energy and endurance, improves concentration, stimulates metabolism and boosts reaction speed
Other: Contains 100 percent of the RDA of Vitamin C; one of the few sugar-, carb- and calorie-free energy drinks available

SoBe Adrenaline Rush
Made By: South Beach Beverage Company
Size: 8.3 oz.
Color: Fluorescent yellow
Taste: Bubbly, lemon-orange taste, with a powdery after-taste
Special Ingredients: Taurine, Ginseng, Guarana (seed of a Brazilian plant that is natural source of caffeine), D-Ribose, L-Carnitine (amino acid), Inositol (B-vitamin)
Caffeine content:
Claims: Energy supplement
Other: Contains 100 percent of the RDA of Vitamin C

Elements Rain
Made By: Snapple
Beverage Company
Size: 18 oz.
Color: Clear
Taste: The flavor is listed as agave cactus, although it tastes like a cross between pear and apple juice; one of the few energy drinks with no carbonation
Other flavors: Metal (orange), Venom (citrus), Fire (fruit punch), Subzero (cherry) and Meteor (tangerine/grapefruit)
Special Ingredients: Ginseng, Taurine, B Vitamins
Caffeine content:
Claims: Increases energy
Other: Contains 10 percent real juice

Amp
Made By: Mountain Dew
Size: 8.4 oz.
Color: Day-glo green
Taste: Amp is made with regular Mountain Dew's base flavor, so it's no surprise it's got the same lemon-lime taste; Amp is a bit tangier, and is carbonated; not too sweet
Special Ingredients: Maltodextrin (complex carbohydrates), Ginseng, Taurine, Guarana
Caffeine content:
Claims: Increases energy
Other: AMP includes a B vitamin called Riboflavin, which makes AMP glow under black light; certain graphic elements on the AMP can will also glow under black light

Red Bull
Made By: Red Bull
Size: 8.3 oz.
Color: Yellow with a cola-brown tinge
Taste: Most medicinal of those tested, bubbly, with a syrupy mouth feel
Special Ingredients: Taurine, Glucuronolactone (a carbohydrate)
Caffeine content:
Claims: Increases energy, improves concentration and reaction speed, stimulates metabolism, improves vigilance, improves emotional status
Other: Red Bull was one of the first energy drinks to hit the market, it's also one of the few to claim to improve "emotional status;" also available in a sugar-free version, which has no calories