Just so you can see how it's done, and in case you're too busy to read the introduction and background.
The best book ever: The Return of the King, by J.R.R. Tolkien. (Where I don't have a specific link in mind, and none is suggested, I'm going to link to the first site that comes up on Google.) I would pick all three of these books, plus The Hobbit, but the category here is best book, singular. So I picked the penultimate one. Why? Because I've read it probably 10 times in my life, and I won't read it without reading the first three first, which means I've read the quadrilogy (which may not be a real word, but I don't know what to call them otherwise) 10 times, and that's no mean feat, so that gives you an idea how great this book is. And not just that. Because it has the charge of the Riders of Rohan in it, and the eagles coming to get Frodo and Sam, and the last stand of Minas Tirith, and because it has a grandeur and sweeping scope that manages to pull the whole set together into the most compelling quest story ever, and one which looms over every fantasy story since then. And after all of that, after the battles and Mount Doom and the parlay and Denethor and Saruman and all that, Tolkien brings it back down to earth, down to Middle Earth, by taking us back to the Shire in a long epilogue that should get slow but never does.
Best Hamburger (Fast Food): Now, remember, these categories are going to be somewhat provincial, because I haven't been everywhere, but I have been around and we're going to ultimately vote on these, so list on in your neighborhood. Me, I'm voting for a Kopp's cheeseburger. These are so good that I once rollerbladed 20 miles to get one. I will drive, over an hour, to get one. I manufacture excuses to go to Milwaukee to be able to stop in and get one. They are roughly four-inch diameter slices of burger heaven. The bun is soft but not soggy, and thin so the bread doesn't overwhelm the burger. The burger is slim. Not skinny, but slim, so it's cooked evenly and doesn't overflow with juice or soak the bun or fall apart when you bite it. It's best with everything on it, but get it however you want it and you will never regret it. When I went away on an internship during college, and was gone for four months, the very first thing I did when I got back was go to Kopp's for a burger. I did that before going to see my family. They're that good. And get the onion rings with them.
Best Novelty Pop Song: I was going to go with The Hamsterdance, a song which I love so much I've got all three versions of it on my iPod and all three are rated 5-star, which gives it a rare position in my music, but even as I was getting ready to type that, a thought popped unbidden into my head: Disco Duck. A song that was popular, God, when I was seven and I can still hear it in my head: "Everybody's doing the disco duck!" And then as I was thinking about that, I remembered Snoopy vs. The Red Baron. Which I can still sing by heart, and I can even remember what the 45 looked like. Yes, I used to own 45s. And Snoopy vs. The Red Baron has to win out, because we used to put the record on my parents hi-fi, which was almost as big as the sectional couch I have now -- all that music listening equipment, 8' long and 2' wide and 3' tall, and now I listen on an iPod that's smaller than my wallet -- and sing along with it, and dance, and picture Snoopy on his Sopwith Camel/doghouse airplane: Curses, foiled again! And it's only because of Peanuts that I know what a Sopwith Camel even is, and the song is part of that, so I'm going with Snoopy vs. Red Baron.
EDIT, 6/29/06: In an effort to continue making this The Best Site Ever, I've located a version of "Snoopy vs. The Red Baron" that updates the original in a novel way. The quality is not great, but it gives you an idea of the song. Go to iCompositions and download it for a taste of what I'm talking about.
Edit, 5/8/08: Found it on Youtube!
Now jump on in here and join me.