1 - iPhone 3G. I've become attached to it for a variety of reasons. For one, the constant Internet access is great, it lets me keep up to date with email and Google Reader. It's a good entertainment device, as I have plenty of games across a wide variety of genres. I use it to take notes, to take pictures of things to write down later, to look up words to prove my English teacher wrong, to look up Spanish words when I don't know them, to find what a song is to listen to later, and that doesn't even cover the great music-playing, video-playing, and phone abilities. I have an external battery for it, so I can go for 7 hours per charge, with 3 extra charges in the external battery. It's fantastic.
To a lesser extent, I cannot live without my MacBook Pro, simply because a larger screen has its place. I have a feeling my Dell Mini will take the place of my MacBook Pro as my main computer for everyday use. I can't wait to receive it!