All of the apps in Windows XP Pro are HT enabled
From backup to media player, they will all take advantage of it. I have a feeling that HT will become the next MMX...
aka Intel says HEY LOOK THIS IS COOL! and no1 supports it.....
2 years later EVERYONE and there great great great uncle has it, and support for it.
As for me i just got my 3Ghz/800Mhz HT Proc, and love it