iPads are great for businessmen, researchers, or otherwise people who walk around/move around etc a lot and need to read a shitton of papers and stuff. Also, it helps musicians a lot. Obviously, it's MUCH easier to read from an iPad than a normal phone with the larger screen. It's also much easier to pull out, read, and put back than a laptop. Oh, don't forget about boot time or waking-up-sluggishly-from-sleep time.
For musicians, the iPad is large enough that you can read your music off of, yet it's one easy-to-carry device that can store hundreds upon hundreds of pieces. Also, it can even act as a metronome, tuner, musical dictionary, or even act as a little computer if you want to research, say, the birthplace of J.S. Bach.
