Although I am more of a wine drinker, my husband is a beer expert. Years ago when we bought our house, I decided that I was sick and tired of beer bottles (especially cleaning them up after poker nights), so I bought my husband a Viking Kegerator for his birthday. Since then, we have tried so many different beers, we had to buy three different taps. Some favorites:
Smithwick's (pronounced smiticks): not as dark as it looks, rivals Guinness in Ireland and also made by Guinness (only recently became available in the states), our favorite on our honeymoon in Ireland.
Pyramid Hefeweizen: We have a few orange trees out back, great with a few slices.
On tap right now and delicious: Blue Moon Belgian White
I guess it depends if you are into dark or light beers, but these are great if you don't like darks very much.