I have a spare standard battery and battery only wall charger. It's a sweet setup, I hadn't realized how nice it was to never have to be plugged in. I don't regret it. In fact, I actually have three standard batteries now (Had one spare for my D1, and picked up another when I got the D2.)
I do the same. I bought a spare stock battery on amazon for $6 and the charging brick for $4. the battery is small enough to carry around on days I know I'll need extra battery. Alternatively, I bought the seidio 2800 battery too, which I use on days I know I'll be nowhere near a cradle and anticipate heavy usage. That battery is obvious much bigger and doesn't fit in cradles or holsters, but I actually like the heft it gives the phone and don't mind it at all. And it lasts forever.