I think this is an excellent question. Being a "gadget" guy, I am usually on board with trying to purchase and incorporate technology into PE. However, I beleive you must stick with the things that you are comfortable teaching and build from there. It is way to exspensive to try multiple ideas during a school year. The resources will never be used and the money you spent will be wasted. Also, make sure kids know how to calculate their own heart rate manually by looking at the clock and finding their pulse. Heart monitors do this for them and they may miss the whole idea of target heart rates. We have built our weight room with game bikes and DDR's and the school has purchased an IPOD for our department. This is a good place to start if you are thhinking of purchasing a few things.