Simple and effective programming tools.
Standardised APIs for all aspects of the computer: graphics (2D, 3D), audio, input, system (hardware, memory, ...) management.
Stability. (Old Amigas just don't cut it.)
Simple and effective office and internet suite.
Simple and effective productivity tools (music and DVD player, CD/DVD-burning program, paint program, scanning program, ...)
Ports of Unreal Tournament 2003, Civilization (all versions), Diablo II; good implementations of classic card- and boardgames such as backgammon, chess, Monopoly, etc. (Rather like Minesweeper, but a little different.)
Simple price: $500 at most.