They are the wave of the future... Tss...
Now how (un)convenient is a widescreen? Umm, let's see.
- Website reading: obviously, they were designed with a 4:3 in mind. But worse than that, reading on a 16:10 screen is not convenient. I don't see what's natural about reading with a wide-angle screen. It's unpleasant and requires extra effort. Unless you resize the window and find out that you need to scroll far more often than with a 4:3 screen. Yahoo! Now that's progress and future.
- E-mail, business, etc.: widescreen is a waste of space. Unless your e-mail titles are 100000 characters long, in which case perhaps it's time to reconsider your e-mail titles.
- Text editing: just like for website reading, writing a text on a wide-screen is not convenient. Side-by-side? Umm... Right. Unless you have a very high res screen, in which case text is microscopic, side-by-side is barely convenient because you have to scroll. Let's be honest, the side-by-side feature is rarely used. Or perhaps you're good enough to write your novel on one side and that Happy Birthday letter to your grandma on the other?
- Picture viewing: my modern digital camera is 4:3. Over 90% wallpapers are 4:3. So it's either cropping or cool black bars and a good part of your screen is useless.
- Gaming: this depends if the game supports 16:10 or not. If it doesn't, you're screwed: black bars again. (Gotta love these!) Or distortion, in which case it's kind of useless to have an expensive video card to get a distorted image.
- DVDs: OK, now here is where widescreen has a point, though there STILL are black bars. Less than with 4:3, but the black bars are still here. Not to mention I have 4:3 DVD content, which looks absolutely bad on a 16:10.
In short, widescreens are really good at nothing. It's a marketing gimmick, a new useless technology that no one asked for. But they look better and they earn you bragging rights (hey, lookie me, I have widescreen and you don't). Granted, it looks good - until you actually try to make use of the "extra" screen estate. I'll try to stay away from widescreens as long as I can, though I'm afraid it will take over eventually.
Microsoft found a way to use the widescreen format, though: in Longhorn, you'll have a huge bar on the right part of the screen that is mainly used to display a huge but ugly analogic clock. Now that's the future

(I'll keep my existing taskbar, thanks.)