Diablo 2, Warcraft 2 BNE and Warcraft 3 were all good on XP.
Warcraft 3 in their later patches removed XP from the table, but it can be played on an XP machine to a certain patch version.
D2 is about to be Resurrected.
Other fun games to play on XP are:
Lords of the Realm 2,
Lords of Magic,
Age of Wonders 2,
Magic the Gathering: Duel of the Planeswalkers.
Baldur's Gate 1 and 2,
Icewind Dale,
Guild Wars,
Age of Empires,
Torchlight 1 and 2,
Starcraft 1 and 2,
Spellforce,
Diablo/Hellfire,
Warhammer.