Apple iPhone 4 
It just re-read my opinion on the iPhone 3G; I mustn't have had my Wheaties the day I wrote that because I don't remember disliking it that much. Then again, my experience with the iPhone 4 over the last year may have washed any those 3G unpleasant memories.
I liked my 3G. I love my iPhone 4.
The camera is now good enough and then some. In my review of the of the 3G I claimed that it was not a substitute for even the most basic digicam. That's the biggest change in my book. I can now leave the house with just my phone in my pocket and not feel like I need to bring a camera too. Of course, if I'm going out to shoot I'll bring a 'real camera' but in a lot of situations the iPhone 4 is more than adequate. Did Apple just kill the slim digicam market?
And while I'm asking, did the iPhone 4 kill the Flip video camera market too? For a video dabbler like me the 720p video capabilities of the iPhone 4 are amazing. Combine the capability to be able to capture HD video with the ability to edit it (in iMovie) and post it directly from the iPhone to Vimeo or YouTube and the Flip looks fat and out of shape. The iPhone really is a digital movie production suite in your pocket. You can even color your footage and apply real time retro effects to the footage you capture. To those who say, "Yes but you can't lock or fix the exposure, focus or white balance." I say, 'Have you tried FiLMiC Pro?'
But back to its ability as a still camera. The native camera app is OK but it is the third party camera apps that make it fun. Instagram is a force to be reckoned with - it is putting the fun that Flickr seems to have lost back into a visual social community. With your iPhone and these apps you find yourself trying things you wouldn't try with a real camera and PhotoShop. Subtlety goes out of the window but the fun factor goes through the roof. You can take a shot, edit it, apply groovy filters, post it to the interweb and get feedback in a matter of seconds. You don't have to take yourself so seriously anymore, after all you're just using you camera phone. No one gives you a second look while you're shooting in public anymore and you don't feel self-conscious about just grabbing a shot of just about anything. Suddenly the camera gets out of the way any you just enjoy being creative. Is what you're producing art or even good photography? Who cares when you're having this much fun. I am amazed and inspired every day by what people produce using just their iPhone.
What a turn around in just two releases. The 3G was no substitute for a real camera - the iPhone 4 is a real camera.