Spent a couple of months just building up wrist and grip strength to deal with a small wrist injury I got last September that kept twinging when I put sideways pressure on the wrist. Since I started working out/building out muscles in that area it feels much better. It had previously been hindering any significant use of free-weights.
I tore my rotator cuff (in the shoulder) about 4 years ago, and I'm still really careful about upping weights on my upper body stuff. You can work around stuff like that to a point, but my upper body is absolutely behind my legs for now. Like I said in the OP though, heavy hiking and biking are my favorite athletic hobbies, so it's not a big deal for me.
The worst part of injuries like that is if you ever push it too far and hurt yourself again, it will probably be worse than the first time. Doesn't help that my dad recently got rotator cuff surgery, and my brother has injured his in the past as well...