If you were to have just one beer glass, I would say these are the most regarded as being engineered to enhance the beer (etchings to continually renew the head, space to trap the aroma and deliver it to your nose, the lip pours the beer on your tongue starting at the tip to hit all your taste buds and holds the head back allowing the liquid to come under it, etc)
The Duvel tulip, which many call the best beer glass ever made. Can be bought separate, or even better, free in a gift pack.
The Dogfish Head glass, similarly engineered. Can be ordered off of their website.
Finally, the Sam Adams perfect pint. I was happy to recently acquire one on my visit to the brewery! Otherwise pretty easy to order online or find in a good beer shop.
Hope that helps!