I like all of them, I hate to call one 'worst". Also I was spited by Pyrenees. But here is my list.
1. Black Mamba: I really like how it keeps up it's speed the whole ride. The inversions and the turns are sweet and I love going through the buildings up the lift hill too. Not to mention it has the best themeing on any B&M i've ever ridden.
2. Banshee: Just rode it in August and I can definitely say it is a very unique, intense, and fun experience especially at night. The heartline roll is just so weird and awesome and the forces in some parts of the ride are super intense.
3. Nemesis: Most of you in the UK have ridden it so you know how you can't quite explain why Nemesis is so great, it just is. It's really intense and that zero-g is amazing. I love how low to the ground it is too.
4. Montu: All around great coaster, I love every single part of it. The g-forces are great, the inversions are great, I really like it a lot. Best batwing element on any coaster ever. I love the variety of elements.
5. OzIris: The drop is really good on this coaster, I love the whole "immelmann, loop, immelmann" pattern in the first part of the ride. I love both of the zero-g roll's and I also like how it doesn't waste the end of the ride with a bunch of boring turns. Took me a while to debate if I liked this or Montu better, but I think I like Montu a tad more.
6. Katun: I agree with Gavin about feeling a little nauseous afterwards but other than that this coaster is a bundle of joy. I also agree with Gavin about it having the best drop on a B&M invert. It's got some crazy g-forces and is a fun ride throughout.
7. Afterburn: Afterburn is a kick ass B&M invert. It has great g-forces, a great zero-g, and of course my favorite inversion, a batwing. It has a pretty decent drop and some nice tunnels. I also really like the trains for some reason, why is that?
8. Alpengeist: Alpengeist is an extremely intense and forceful B&M Invert. The drop is really good, it has some great forces, all around good coaster. I thought the cobra roll was a little bit jerky but I don't like cobra roll's in general anyway.
9. Patriot: This coaster kind of reminds me of OzIris, doesn't waste the ride with boring turns at the end, has an awesome zero-g, and is pretty forceful too. I actually like these quick roller coasters because I want to keep riding them over and over, and I guess that is the explanation of why I rode this 12 times in my last visit to Worlds of Fun. All around fun coaster.
10. Talon: In case you haven't noticed, Cedar Fair generally has some really good B&M inverts. This one reminds me a lot of Black Mamba, it never lets up it's speed, and it It has some great elements. It is my favorite roller coaster at Dorney Park.
11. Batman: The Ride clones: Good fun, decent forces, just an all around fun ride. Who doesn't like a nice Batman clone? The only thing bad is it has that part at the end with boring turns but the rest of the ride is fun.
12. Flight Deck: A surprisingly intense, short but sweet, and fun roller coaster. I love how it goes over the lake. There are more forces than you may expect on this coaster, in fact I have even heard of blackout's on it. Good coaster.
13: Monster: This coaster is overrated. It's not bad at all, but not great. It had some good forces to it and all, but the only reason why it is so re-rideable is because you are at Walygator Park, AKA Crap Coaster Central.
14: Hungarian Horntail: Not as bad as people make it out to be, I have heard people say it has to many straights and doesn't have a lot of forces, but it was a pretty decent coaster to me.
15: Chinese Fireball: The other Dueling Dragon, I found this one to be more forceless than Horntail and the elements not being as good as the ones on Horntail. It was alright.
16. Phaethon: The zero-g is great but the rest of the ride is just "eh". Not a bad coaster, just could have been better. Kinda like sex without the happy ending part...
17. Nemesis Inferno: It's okay. Nothing to special, and obviously the original Nemesis is a lot better. It has some decent forces but one of the lesser rides at Thorpe Park. That does not mean it is bad, it just isn't too special.
18. Great Bear: I don't like the whole "g-forces on your legs" thing. It feels really weird and uncomfortable. I do agree the ride kinda dies in the second half, but the coaster overall is OK...
19. Silver Bullet: Not as bad as some people say it is, but yeah it is pretty forceless. I actually usually ride this one when I am kind of tired from walking around, so I can just sit down and enjoy the wind in my face.
20: Raptor: It is barely OK, it is the opposite of Black Mamba or Talon, on this one it loses it's speed throughout the ride. Sometimes when I make a trip to Cedar Point I don't even bother riding it.