Funny thing is I rarely use the iPhone 4 or iPad as a source.
But both are indispensable.
I had no intention of buying the iPhone. I had a RAZR which I loved. I still have it, actually. I like its form factor better than the iPhone and it is a lot more comfortable to talk on. But I used the iPhone for about 15 minutes at an Apple Store and gave them $600. Impulse buy, but it was so much more usfulmthan the RAZR. I'm on my third iPhone and it is still the most useful gadget I have. It's serviceable for short phone calls, but I use it constantly. I love the apps, too. Especially the HP 12C emulator - having a 12C with me always is incredible. I also like Weatherbug immensely.
Another funny thing is that after using the original iPhone for a few months, I started wanting a bigger version. Like some kind of tablet.
And Apple was nice enough to make one.
Though I had serious buyer's remorse over the iPad for a few days. I had an iPhone and MacBook; where would it fit in? It turned out to mostly replace the MacBook.
So I think the MacBook is on the way out. I think I'll sell it and roll the cash into a new Mac Mini. When traveling, the iPad and iPhone replace a laptop easily. At home, the Mini will be fine as a desktop and I'll set it up as a media server, too, wih the iPad as possibly the best remote control ever. (I also have the AppleTV.)
I love iOS. The functionality is amazing. Sure, there are some limits, but it covers about 90% of what I need and OS X picks up the rest.
I really look forward to next year's iPhone. Siri will be useful to me and I'm hoping that Apple will integrate Siri across the rest of their devices. I think they will. *Gets out crystal ball* I think Siri is Apple's Google-killer. Siri is still in beta, but is growning and becoming more and more intelligent as she processes more and more requests. People are going to get used to asking Siri for things, which is faster and more convenient than typing in a search query. Siri will take a big bite out of searches. I'm sure Google will develop something similar, but it probably won't have the tight integration Siri has.
What I really want is Siri integrated across all products as well as some home integration hardware. I'd love to use voice commands (Star Trek style) to control the lights, HVAC, appliances, and electronics. If Apple doesn't do it, then a third party add-on will. Probably soon. I imagine Siri will be integrated into apps shortly. I'm thinking we'll get all this in a year or two.