I'd place Windows 7 and Linux Mint Debian on the same level. They're both solid, look nice, and give me little problems. I don't think they quite got to the level of Windows 2000, though, which was my favorite.
It was as horrible as everyone said it was, and then some. I was too young at the time to really pay attention to what anyone was saying about it, but when I installed it, I was aghast. Not day #1, not day #2, but after blue screen after blue screen by day #3 I knew I missed Windows 98. I soon scrapped it when a co-worker gave me Windows 2000, after listening to my complaints, and I instantly knew that I made the right choice in dropping that PoS OS.
Now, I think Vista wasn't as bad as everyone made it out to be, and certainly not nearly as bad as WinME. It wasn't great, but it gave me far less trouble than ME ever did.