When I first read the trilogy, I read everything in order...
...except when it came to the RotK, where I skipped Book 5 and proceeded to Frodo, Sam, and Gollum....
I think I did that because I happened to have an entrance exam, and I was applying for a scholarship--you know the usual stress when reviewing for those kind of tests. However I wasn't able to put down RotK because I can't wait to see what happens to the Ring... till my dad locked up my books for me to seriously review. I finished all LOTR several months later, when the scholarship results were given... and I was sooooooo glad they did.