Some of you are really stupid.
Multitasking almost drains no battery life when you get out of an app - it is by far the best thing; simple to use, and awesome multitasking benefits. Most importantly, instant app access - no need to wait anymore for it to load.
Maybe learn how it works before calling others stupid? Multi-tasking doesn't auto-magically give all apps the ability to reload quickly. Only apps which take advantage of this aspect, as programmed by their developers in an iOS 4 update, gain this perk. And even then, it only works if the phone didn't need to reclaim the RAM the app was hibernating in before you went back to it.
On a 3GS, it's usually the case that my "minimized" app had to give back its RAM before I got back to using it so I almost never benefit from fast re-launching in any apps that actually take awhile to launch. The only apps which don't get purged are so lightweight that they take only milliseconds to launch in the first place. It really is a worthless feature without more RAM.
Also, even minimal battery drain is too much, especially if it's a dozen apps all draining my battery. That can add up to significantly reduced battery life. I don't even turn on Push notifications because I don't like the battery drain, and compared to my friends using Push, my phone lasts considerably longer. I'm talking days longer. How much drain would you consider Push to be? Almost none? Yeah, if minimized apps use even half of what Push does, that's way too much to be worth it except for key apps I want to leave minimized.
redscull, I think you're putting too much effort into multitasking. The design of multitasking was done so that you wouldn't worry about those things. You need to have faith in the system and it's design and stop thinking about multitasking on the level that you are used to. This is a new intelligent system designed to allow you the functionality you require without all the overhead and thought that you may be used to. You should adjust the way you think and let the system manage the resources as it has been designed.
Yeah, that's hard for me to do, as a software engineer and computer power user. I did try it though, as hard as it was. And it doesn't work for me. I don't like the reduced battery life (not theoretical, I can tell the difference). And I hate that, now that I have apps which really do minimize/hibernate, Safari's RAM gets purged before other apps, meaning I have to suffer a page reload pretty much every time I go into it. If I could actually close my other apps when leaving them, since I almost never care about minimizing games, I could ensure that Safari, the one app I really want to minimize, would still have its pages in memory. Safari reloading a page, particularly a big one, wastes my time, my no-longer-unlimited bandwidth, and my battery.. all because Angry Birds now minimizes instead of closing when I leave it.
I agree that the design should have been such that I shouldn't have to worry about it. But they failed at that. The design was done so poorly that now I'm forced to deal with it frequently.