Ill look for some references this afternoon. My personnal experience is charging and discharge cycles have very little effect on life. Keeping it on charge or using it everyday has little effect on life. The biggest factors are age and temperature. Heat kills li-ion batteries. Keep your edge cool (not cold). Leave the battery 70-80 percent charged when in storage. And replace it after 3-4 years. There is no way to get around replacing the battery...other then teathering it to a wall when the battery dies or not using it.
My advice is to use your eDGe and enjoy it. Charge it up at night when you go to bed and don't worrry about the battery. Its like being woried about getting old
On the SD card topic, I use a 32GB sandisk class 4 with no problems.