I own a WiiU just because it is backwards compatible with the Wii, needed a new console around the time of launch and decided to invest early in the new system. Always had a PC of some sorts since I was a little kid, and my mobile gaming started with the classic Snake; so those are just evolved purchases.
Next-gen:
WiiU = backwards compatible, 1st party titles, and hoping for stylus games (Art Academy, Picross3D)
mobile = backwards compatible (tablet next year), timewasters + indie games
PC = backwards compatible, downloadable + indie games
Last-gen:
Wii = return to consoles (previously owned: Mega Drive/CD), IR + motion controls (new play styles)
DS = return to handhelds (previously owned: Gameboy), stylus gameplay (sudoku, picross, etc)
PC = backwards compatible, flash + downloadable games
mobile = timewaster games
2 gens ago:
PC = backwards compatible, PC gaming
mobile = mobile gaming
