Best for heartburn...
There are two main types of meds for heartburn (PPIs - proton pump inhibitors): Protonix, prilosec, nexxium and the other are H2 blockers (like Zantac).
The PPis are better in terms of strength and long term effectiveness however the H2 blockers tend to work quicker. So if you want quick relief take something like zantac or maalox, but if you want something that works daily you can use one of the PPIs. Also the companies will tout nexxium (the purple pill) as being the best, but to date none are better than the others so just choose the least expensive one for you.