And if you know me and are confused, no, I didn't buy an iPhone... I still just have an iPod Touch. But for the sake of argument (and to boost any potential hits to this website through a search engine), I'm just going to refer to the device as an iPhone and leave it at that.
Anyway... here are somethings I'll never use an iPhone for:
Read a Comic Book
There are numerous applications devoted to putting comic books on an iPhone, from simple readers that allow you to download digital versions of the books to just the books themselves. Some of these applications are better than others, but all are completely worthless in my opinion. If you want to read a comic book, chances are good you like comic books. The screen of an iPhone is about one tenth the size of a standard American comic book, so the art either has to be shrinked down to the point where it's too small to read, or stretched out and pixelized so it's too ugly to look at. I definitely think that digital downloads will be the future of comic books, but not on an iPhone. No way, no how.
Read a Novel
I have the Kindle app, but I only use it for one reason: To send samples of novels to my iPhone so I can see if I want to go to a bookstore and buy an actual copy for real. It's a neat feature that allows you to read the first twenty or so pages of any book that is currently available for purchase on Amazon's Kindle store. I've never made it through more than five pages or so of any "book" on my iPhone, however, because it gives me a headache and just feels all wrong. The text is either too small to read, or so big that you have to "flick" the page after about two sentences. Sometimes I'll try to read an iPhone book while sitting on the toilet, but I'll usually just give up and read the back of a shampoo bottle instead.
Play any Game More Involved than Tetris
I love videogames and I think the iPhone has incredible processing power, but most games for it just aren't very fun. There's just something unpleasant about rubbing your finger across the screen for longer than, say, two minutes at a time. Also, the fact that you have to put your hands in front of the screen to control the games means you can't see what you're actually playing much of the time. Tetris is fun. Solitaire is fun. Some of the other puzzle games are fun. But I'm not going to play Metal Gear Solid on this thing, thank you very much.
Watch a Movie or TV Show
Apple obviously assumes somebody is watching stuff on their iPhones, because whenever I actually download an HD episode to watch on my computer (hooked into a TV!), it automatically downloads the SD version alongside it. Again, thanks, but no thanks. First of all, if I actually want to put a movie or TV episode on my iPhone, I have to remove about half of my music just so it will fit. Second of all, the screen is smaller than the palm of my hand! Who's watching movies on this thing? I own a Widescreen TV for a reason: I like being able to see what I'm watching.
But that's just me. I don't even have an iPhone.