When you'd buy the Zoom H2, would you be using the internals? When you're going to record loud arena shows, there's no way the internal mics of the H2 can handle the sound pressure level. Invest in some cardiod mics for arena shows, omni/binaural mics pick up too much crowd noise and the reverb of the arena itself. Unless you're standing upfront, you'd be better of using cards.
For the recorder, I couldn't give you any advice, I use the H2 only with external batterybox and mics and haven't heard of the Tascam DR-07.