If I had a Pee-S-Pee I wouldn't bother running it off the battery anyway. I'd have it plugged into the wall or car or whatever at all times instead of fighting with keeping it charged all the time. In essence, I'd be using it just like a console, except it would be a handheld.
That's basically how I see it -- it is a handheld, definitely, but it isn't a portable. It should be called the PSH (Playstation Handheld), because calling it a portable implies that it has a great battery life, and that just isn't so.
But since you can't ever be far from an electrical socket when you use your PSP, why not just use a PS2 instead? Sony just doesn't get it.
I wouldn't be surprised if the PSP's sequel uses the Cell processor, and Mini-blu-ray discs, and requires fuel cells or even a portable fusion reactor to play. It would get so hot that in order to play it you would have to wear oven mitts.