But newer is not always better. Apps I refuse to update:
"Removes the dictionary from your list of books, and no longer lets you open the dictionary and read from it. Update notes do not disclose this." -925925
"Maybe if you guys stopped trying to cram in an escalating amount of bloat and advertising [with every update] the app would continue to work properly." -Shawhan Moleski
The loading time got so bad, I just deleted it and replaced it with the free Merriam-Webster Dictionary, which is much faster.
"Before the update, you could end an activity [quickly]. Now, ending an activity involves a convoluted multi-step process, where one has to decide whether to share the activity on twitter, Facebook, or some other mindless social website." -FlyDogAZ
"All you did was add pop up banners constantly." -Nyr9440
Other apps I'm not updating: Bejeweled and Drop7 (Facebook integration: no thanks), Shazam (now limits you to 5 music tags per month).
The iPhone really needs an IGNORE UPDATE button. I’ve submitted feedback to Apple requesting this. Now it’s your turn.
Addendum: Two years after I wrote this, Apple released iOS7, with optional Automatic App Updates. So what I do now is simpler. I don't like managing updates. If an app upgrade makes it worse, I just delete the app and replace it with something better:
I replaced Kindle with iBooks. Pandora with iTunes Radio/Soundcloud. Dictionary.com eventually got a bit faster, and Merriam-Webster got slower. I usually use Siri to look up words now. Runkeeper was replaced with Nexercise, but both are pretty slow. With Apple's new M7 Motion Sensor, I suspect they'll be releasing some sort of fitness app/watch soon. Mapquest replaced with Apple Maps.