Since you likely haven't acquired a sophisticated beer palate yet, I would stick to the lagers as well as the hefeweizens (since you mentioned you liked the Penn Weizen).
Easily drinkable lagers are:
Rolling Rock
Molson Canadien
Pilsner Urquell
Stella Artois
pretty much in that order in both taste and price.
Hefeweizens:
Blue Moon
Pyramid Hefeweizen
Ommegang Witte
If you want to branch out to heavier-bodied beers:
Fat Tire
Sierra Nevada Pale Ale
Anchor Steam
The most important thing is to try different styles and find one you enjoy both the taste and the price range. Likely if that bar has over 100 beers, they will give you shot glass size samples so you can try several different ones and find one that you are comfortable with.
Beer is a very personal choice and different ocassions can call for different selections. Go with what you are comfortable with, try different things, and don't worry what others say.