Um...mine has.
I don't use my notebook anymore, save for iTunes home base (which will soon be replaced by a more family-sized decked-out iMac). Remember, the scenario is an individual in a family, who has access to a family-shared computer as needed.
It's my music player. Podcast talk shows & audiobooks in the car, noise-blocking trance podcasts at work, background music at home (looking forward to "pushing" music from iPad to AirPort-tethered stereo).
For individual viewing, I watch streamed Netflix and YouTube videos on it. No bedroom or den TV needed. For $99, will hook an Apple TV to the house screen and push videos there from the iPad.
What few computer games I play are on it. Epic Citadel shows how robust those will be soon.
With Skype and Whistle, it's my phone half the time now. People are startled at how clear calls are when I use it over regular cell phone (no, I don't have an iPhone).
Physical media is giving way to digital on my iPad. Have about 200 books (all quality free classics, thanks B&N) on it, looking forward to reducing my 26 stuffed bookcases to 1 (leatherbound/old classics only). The whole CD collection is on it. Soon I'll rip all the DVDs to a pocket hard drive, and copy in-queue movies to the iPad (see above).
No furniture needed to support bulky gizmos to do all that, just one slim iPad in a nice leather case. It goes everywhere with me.
Yes, I'm doing all that now.