Are you interested in regular blends, flavored or extra bold?
For a really good all-around regular coffee most people really like Nantucket blend. Also, Caribou is really good. If you like flavored, I would go with something basic like a French Vanilla.
If you are interested in an extra bold blend, Newman's Own Extra Bold is really good. Also, as the previous poster said, you can always get a variety box.
I am the (self-appointed) Keurig queen and have probably close to 300 K-cups in my cabinet as we speak. I think I have tried just about every flavor and can give you some other recommendations if you are interested.
Just to let you know, even if you aren't much of a coffee drinker yourself, Keurig also sells teas and hot chocolate flavors. However, I think the teas are expensive for what they are, so I just put a tea bag in the My K-cup filter and brew plain water through it. It works great!
A great website for ordering online is
www.coffeegiant.com. Free shipping with no minimum purchase and if you sign up for emails they send you specials just about every day. The boxes you buy online usually have 24 k-cups in them, the ones you buy at Kohl's or Bed Bath & Beyond generally have only 18 k-cups. So although the ones online are around $10-$11, you get more in them.
Any questions, let me know!