I love two-chord progressions. They're so simple, yet effective.
Such as: Cm7+11 - Fm7+11, Gm7 - Fm7
My favorite chords are the "[key]m7+11" chords, where you take out the root, add the 2nd/11th, same thing, and flat the seventh. It's so full.
I also love the blues head format. The chords are...