For those who tested out the N95 for how long it lasts as an MP3 player, was the phone in Offline mode? Reason I ask is that doing so will result in dramatic differences, and I have a feeling it'd last a lot longer than 5 hours. So, for Dinan's situation, a flight with the N95 as a standalone MP3 player may work out just fine, or at least be a bit better than the reported 5 hours since the phone will be in offline mode for the duration of the flight.
One of the big things I've noticed while playing with battery life is the effect keypad tones have on it. Keypad tones will MURDER the battery life of your phone. After a little over 4 hours of random heavy usage including texting, GPS, WLAN browsing, and a few brief phone calls, I was already down to 4 bars.
There's also some "rules" that may not be so apparent when dealing with a device like this with a sensitive battery. If you're going to be using the phone around the house in one area, throw it on the charger just like you would with a laptop. No sense in draining the battery if you don't have to. If you're going to be in the car, on a call, on GPS, or not, throw it on the car charger. Even if you're on a call, listening to music, using a Bluetooth headset, AND*using the GPS, the phone will still charge at the same rate you're depleting it, at least. If you know you're going to be away from home all day, bring your charger with you. This may not be necessary if you're going to be in the car a lot, (I've never had to do this as of yet) but if you're going to find yourself at a friend's house or somewhere without a lot of phone activity, throw it on the charger. A solid half hour of charging will give you back a lot of bars to last through the rest of the day.
It may not be the best battery, but it certainly is manageable.