When I first got my I phone 3G (2 years ago) I spent a great deal of time downloading apps, not using them and ultimately deleting them. I ended up with a core (a still ridiculous 60 or so) which I kept.
A month and a half ago I got my iPhone 4S. I spent a great deal of time downloading apps (again). The advances in technology (through the iPhone 3GS and 4) means that the phone and the apps work together in a way they didn't before. I deleted a lot of the new ones; but I also re-discovered some old ones which work better than ever before with the latest operating system.
So now every so often I turn my eyes skywards once the sun has gone down and see what is in the sky. The app tellls me the constellations; of course if I want the names of the individual stars then I'll need another app!