(I see that ChessGenius by another of the greats is also on sale.)
Others include Bejewelled 2, the classic 'match three' puzzle. Quell Memento and EDGE are also good.
This entry was originally posted at http://lovingboth.dreamwidth.org/534682.html, because despite having a permanent account, I have had enough of LJ's current owners trying to be evil. Please comment there using OpenID - have and if you have an LJ account, you can use it for your OpenID account. Or just join Dreamwidth! It only took a couple of minutes to copy all my entries here to there.