Oh, you're one of THOSE people. Everybody seems to come at the iPad from a different angle. You're going to want Penultimate:

As for battery life, I don't think multitasking will hit it hard at all. The biggest drain on the iPad battery is the screen. So cranking up the brightness because you're in a well-lit place will hit the battery harder than surfing the web while you stream audio. You'd have to really be trying to kill the battery to get less than 8 hours out of it. An hour of Netflix streaming uses up less than 10% of my battery, because the fact that I watch in dim light more than compensates for constantly using the WiFi.

If you want a laptop replacement you need to get a tablet with a full OS, not a mobile OS.

Which means your only option right now is to wait until the beginning of the year for decent Windows7 devices... or if you want MacOS then go with the new Macbook Air.

Personally, I'd wait to see what the next installment of Android has before I make any decision as their Gingerbread tablets will all be out by end of year as well.

But realistically, for school use, you need a more fully functional laptop. In the long run, using a tablet will prove to be more complicated.

AS for your specific multitasking, yes, the stock iOS4 experience does a horrible version of multitasking. However, jailbreaking it would fix that. As for mobile OSs, Android is the only one where it works just like a regular computer. However, the current line of tablets with Android running 2.2 are not really perfected yet as that version of the OS is not intended for a tablet (which is why they are no bigger than 7").

My advice, again, wait until January to make your decision if you really want a tablet.

It would be good for notetaking but then not good enough for other things. Personally I will buy a laptop instead. Don't know much about ipads to comment on battery life and the new o/s that might have multi-tasking. Just my personal oppinon.