I use, and will continue to use, ATK. The large majority of the apps that I regularly run are on my "ignore list"; there are really two kinds of apps that I kill: ones that I basically never run (e.g. Shazam, ShopSavvy--no point in them lingering if I won't use them again for two weeks) and ones that will GPS-pwn my battery life if I forget about them (e.g. Maps, WeatherBug Elite--I want them to have GPS capabilities without micromanaging their settings, so I just leave it on and kill them as necessary).
Does it bother me that Corporate Calender (huh?) and Visual VM are running in the background someplace? No. I mean, I consider it a tad annoying, but I don't think it hinders the phone in any fashion. So I ignore them, and that's that.
In any event, I really do think that there's a middle ground here. As Ainvar said, use & enjoy your device as you please.
1. ATK used to be a battery-consuming culprit for me (i.e., it was at around 2% of the battery used after a recharge). After I stopped running its task bar widget, though, that completely disappeared (now I just have an app link on the home screen).
2. Anybody notice that the Locale process ("LocaleService") shows up in the device's running services list but not in the ATK task list? What's that about?