usually at home, it will be a K100 or my mvp. when im out or at work though, i pretty much exclusively use my SD maxi keyring with various LR cartos. it works so well, that i will probably pick up a couple more in the near future.
still have a "sometimes" working K200 and various ego twists laying around, but the MVP is my fav. big-ish mod, K100 - fav mech and the SD is my fav all around...