I've been using my iPhone with the 2.x software since it came out a few months back. At first, I wasn't too thrilled with this "upgrade" to my iPhone - my previously speedy and stable device (despite being jailbroken for most of its life) had been converted into a very slow, unstable, and ultimately unreliable product. Then the iPhone 2.1 software came out, and an amazing thing happened...all my iPhone's issues vanished, and it was back to being the device I'd grown to enjoy using over the last year.
For that, I thanked Apple, because this version of the software fixed all of the major stability and usability issues I had with my iPhone.
However, due to the stability of the software, I've also discovered a fundamental shortcoming of the iPhone 2.1 software. Because I now trust the iPhone won't implode, I've found myself installing more and more apps. What used to be 79 programs on my iPhone at the start of this month has become 107 programs--and I expect the number to climb ever upward. But navigating this mess of icons--you can have 16 programs per "page," with up to nine total pages--requires a ton of either swiping or tapping (in the small area between the main screen and the bottom row of four fixed icons).
This is especially true if you try to have some sense of order to your programs' organization. For example, I like to group games together on one (OK, two) screens, "location aware" apps on another, utilities on a third, and so on. This makes programs easy to find, but has the downside of requiring a lot of page navigation when I want to jump from, say, a game on page seven to the Calendar icon on the iPhone's home screen. I've tried to minimize this page navigation by putting my most-used programs (regardless of category) together on the second page of the iPhone's screens--that way, 16 of the programs I use most often are only one page away from the home screen.