I use hd2, still on 5.3 with xp and it works fine. I used to have le on Millinium which was horrible. I found millinium to be very unstable. XP is rock solid though in my experience. The only problems I've run into is from my own stupidity.
With a lot of help, built a new computer and my first session I got 38 tracks at 24/96 with all the automation, edits etc off of a single 7200 rpm drive via the promise controller port on the Asus mobo. Pci buss and system not even breaking a sweat at that point. All the parts only $1240. Try getting that kind of performance from a Mac on a $1,200 budget
cheers,
steve