My regular coffee is Eight O' Clock Columbian Peaks.
It's just the best bang for your buck in a K-Cup you'll find, in my opinion.
My wife and I like flavored coffees, though. We had been ordering from a company called Crazy Cups because they're pretty good for flavored coffee, but she recently decided to look into options to broaden our tasting variety.
She ordered about a dozen bottles of sugar-free flavored syrups (like you'd find at a coffee shop, but more flavors than your average coffee place).
It turns out that my new favorite thing is my regular Eight O' Clock with this stuff.