I'd like to see Blu-Ray win, because its technically superior. While it'll initially be costlier to make players/disks, more volume will make it cheap enough, just like DVD.
However, Sony has this very anoying profit-grabbing habit of only supporting proprietary formats in their devices - like their digicams (Memory Stick), PSP (Memory Stick and UMD) and what-not. This makes me want HD-DVD to win.
On second thoughts, however, I want better technology to win and so, my pick, by a narrow margin, would be BLu-Ray.