If your Dell Streak spends a lot of time in airplane mode, whether because you fly a lot or you use the device as a WiFi-only MID, make sure you turn that mode off when you want to charge the device. Why? Because when airplane mode is on, battery charging is off. So if you don't re-enable all the wireless radios and just plug the Streak into the wall outlet before you go to bed, you're in for a rude awakening in the morning when you see that the battery hasn't charged at all.
Tip: If you fool the Streak into thinking it's in airplane mode by manually turning off the cell radio, which would also let you use WiFi and Bluetooth, then you can still charge the battery.