Yes the battery sucks when you look at older Nintendo handhelds. That does suck.  
But in the day and age when cell phones are the majority of peoples main handheld gaming system, and lets face it, playing any game on you cell phone kills it much faster then 4 or 5 hours.  How could so many people be upset at this? We are used to this, as cell phone users. I think that is where the next head held fight is going to be be, between Nintendo and cell phones. So, in my mind, as long as the 3ds gives me better games then phones (im thinking more along the lines of the online store here) then im sold even with the shorter battery life, if i need to save some extra juice ill just keep the 3d off.  
And the short time is cause when you use the 3d. Keep in mind, when you have 3d on, you are running 3 screens on one system. There is no real point to this post btw. Just think im a bit hype for the next handheld wars to start up, and so far the 3ds has me really happy, lets see what the psp2 and the play phone brings.

Wait, so the battery's supposed to be... not so great? That's too bad. My DS Lite can hold a charge for the longest time.

yeah its not that good, 4 hours or so when 3d is on, 8 or so with out i think.

My DS Lite and my cell phone can go for days without a charge. 
 
Where is your god now? 
 
That's right, you cast him into the deep, dank hole known as "Mobile Gaming."

That's not a good excuse for poor battery life.

" Wait, so the battery's supposed to be... not so great? That's too bad. My DS Lite can hold a charge for the longest time. "

My phone usually lasts 2 days with heavvy use.........even my heavy duty laptop has 3 hrs battery life....i expect a handheld to have at least 6-8

I had a simi long  reply here, full of links and a few graphs of what happens when you play cpu heavy games on phones, but i said fuck it, if there are people willing to lie about there gaming on a phone usage im not going to even try. ....2 days heavy gaming use on a cell with no charge...LoL.  
 
 
Edit, and as was said before, the 3ds has around 8 hours of game time with out the 3d on, good thing they give you that slider to control your battery usage if you know you will be away from a plug for a while.

"  good thing they give you that slider to control your battery usage if you know you will be away from a plug for a while. "

this is the only thing concerning me about this system
 
4 hours is not enough at all

I think it's alright because when i play a handheld i tend to be near a power socket so i will be fine if i carry the adapter with me :)

"

I think it's alright because when i play a handheld i tend to be near a power socket so i will be fine if i carry the adapter with me :)

"