K thanks for the help, though one more question. When i close the PB (im not used to the mac system), does it go to sleep, or what exactly does it do? I heard that you are never suppose to switch off a mac. So if i close it, and leave it plugged in, is it the same thing if i leave it on/open for my battery?
It goes to sleep, yes. All the info gets transfered to the RAM, and a little power is used to keep the RAM from shutting down, that's all. It takes about 1 second after you close the lid for the PB to go to sleep, it takes maybe 2 seconds when you open the PB to 'wake up'. Best of all, it uses maybe 5% battery per 24 hours.
It's true, you're never supposeed to turn off a Mac. OS X is UNIX-based, and UNIX systems never need a reboot, supposedly, they keep on working just as fast. It's true, I've had my 12" PB since June and I've restarted maybe 4x, because when you do a software update you have to restart. Other than that, if I'm not using it I just close the lid.
If you just close the lid and leave it plugged in, it's probably better for your battery, since when it's plugged in the battery cycles between 95-100%, just to keep the battery functioning (I think). So it takes longer to cycle when it's closed. But as some people mentioned, it's better to charge the battery to about 50% (it says not to fully charge it before taking it out) and then just take it out until you're going to be using your PB as a laptop.
Good luck with your purchase!