i promised people in irc i'd reveal what my secret paul eres exercise routine is once the poll has reached 100 votes, and now it has, so
i basically use isometrics/isotonics (like the stuff
here), with supplementary cables like
this. about 2-3 times a week. i also walk half an hour a day, mostly cause it helps me think about my game more clearly rather than as exercise.
i've heard (and it's my experience) that the body only improves when faced with new stressors, so i vary what i do every month a bit (there's a wide variety of exercises that you can do with the stuff in the links above). if you keep doing the same exercise over and over you won't really improve as fast as if you change the exercise you do every month or so.
i've also recently been reading about kettlebells and intend to buy one of them eventually, as they seem pretty great and have a lot of varied exercises you can do with them