I like character driven stuff, and really like the sort of continuing characters you get in detective novels. If I happen upon someone I like, I'll stop at the local used bookstore and get more of the same. Sadly, I go in now and have to read a few pages because I can't remember by title anymore.
Parker's Spenser character is by far my all time favorite of the series type though.
Calling it addiction would be understating it for me.
McPhee, if you enjoy character driven stuff you may find Arkady Renko quite compelling. Starting with Gorky Park Renko appears in Polar Star, Red Square, Havana Bay and Wolves Eat Dogs.