I adore the A-10's.
I've actually got a spent 30mm shell in my office a buddy brought back for me from an A-10 that was doing "training missions" in "Turkey"
Yeah, the A-10 is quite the weapon. I would guess that the USAF keeps extending their life due to lack of a good replacement. Radar guided missiles can get jammed, but not much you can do to stop a low flying 30 mm cannon that unleashes depleted uranium shells. Heck, even the engine location was designed to maximize combat survivability (a.k.a. takes a licking and keeps on ticking).
I remember talking to a A-10 pilot at an air show a number of moons ago. He said the counter-acting force from firing the 30 mm cannon is large enough to slow the aircraft by 30+ knots while in steady state flight. That's crazy stuff.