It would be impossible for anyone to have already had a Nook ST for 2 years! I got it when it first came out, which was June 2011.
Anyway, it was perfect for the first year + several months when it started having freezing issues. I have the extended warrenty thankfully so i got it replaced. Then recently i got another replacement because of white lines on the screen, which was appatently due to a scratch. So I've already used the warranty twice and I have 4 months to go. I dont know what I'm going to do once the warranty runs out.
I love the nook touch but sometimes I am so frustrated with it. I love the form factor and how nice it is to hold and read on; I think the physical page turn buttons are awesome in addition to the touch screen. Physically, I absolutely love it I doubt there's any other reade out there that's so easy and nice to hold and read on.
I HATE: the incredibly cumbersome annoying folder organization. At least don't display all the stuff that's already been shelved (not in shelves but in alphabetical order!) when I'm making a new shelf. Drives me nuts.
Using the warranty, I was annoyed at having to call the number and ship my nook to the warehouse. I thought the actual B&N store i was standing in would handle all of that and give me a new nook right there but no dice.
Overall if Nook would just make the shelves a bit easier to set up I would be fine with buying nooks with warranties every 3 years or so.