We cook at home on both charcoal and gas grills, and we like both methods equally well. Some people claim to detect a taste advantage with charcoal, but we really haven't found that to be the case, as long as the two fuels provide a similar temperature range. The manufacturing process for charcoal eliminates its original wood flavor and adds nothing positive in return.
The only advantage with charcoal over the others, in our experience, comes from its firepower. It generates high heat, even with the lid open, which isn't normally true of the gas burners in grills. You have to shop carefully to find a gas grill with the same heat range as any inexpensive charcoal model. We've cooked on several good gas grills, and the results are always just as tasty as those from charcoal.
The only fuel that seems to us to make a difference in flavor is wood chunks or logs. Although a few wood chips added to a charcoal or gas fire aren't enough to flavor food, cooking entirely with wood has an impact. A few manufacturers offer grills meant for wood cooking, and some charcoal models adapt well to the purpose.
The choice between fuels is mainly a matter of mood and personality. We opt for gas for everyday grilling because of its speed and convenience, and use charcoal or wood for entertaining to foster a more traditional, relaxed party atmosphere. If you don't want to deal with more than one grill, pick the kind that fits your personal style and budget. Bear in mind: Gas models that get as hot as charcoal grills are pretty pricey.