So, here's the deal. I use this phone, toy, tool anywhere from 5-8 hours a day. Why? Because there are apps and uses for it throughout the day that just plain keeps it going.
I talk anywhere from 2-4 hours on it everyday for work.
I use the remote to control my iTunes on my home desktop throughout the day instead of logging on to the desktop 6 times an hour to switch songs.
I play games - Monopoly, Tetris, Scrabble, some stupid Poker game I picked up (for free), the paper toss game, Oregon Trail, the Price is Right and Yahtzee.
I've just started using iFitness when I work out to keep track of what I'm doing at the gym instead of hauling a paper and pencil around.
Oh, and the iPod... yeah, use it for when I'm on the plane, when I'm working out, and when I just want to rock!
I can't imagine a better piece of electronic equipment that I've ever bought. I've never gotten so much use out of one thing (and I rubbed the A and B labels off of my original Gameboy...).
All of that being said - I challenge you to find one piece of equipment that will help your life in such a vast way. Do it - and I'll give you a dollar. Or buy you lunch if I like you...