If you like your coffee strong, as I do, go for the strongest they make, green mountain double diamond, or one step below, dark magic.
I save about 57 percent on cost by using the octa flow. It allows you to put your own coffee in and brew.
The one made by keurig sucks, and you have to take a piece of the machine to use. With this one, you just grind and add 2 tbsps of coffee and good to go.
I buy peats whole bean french roast. It puts the costs down to less then half. So in the morning I use the prepackage to get myself going, and after that I use my own coffee.
If you like a good medium blend the caribou blend is very good. (not green mountain)
Good luck Jerry