From what I have ridden, Silver Comet blows everything else away. The first drop is awesome, the double drop after has great air, and the laterals violently slam you into the side of your seat throughout the ride. Excellent Coaster [:)]
I do think that if I rode it, Phoenix would be my favorite coaster though. It is one of, if not the best coaster in the world, and I've heard it has 17 moments of air and 8 ejector hills that slam you against the lapbar each time. Even going into the turnarounds you float out of your seat. It has to be the best ride ever!
and that has what to do with favourite coasters....?
back on subject, best coaster imo (in the UK, that i have ridden) is possibly Grand National. One violent woody and packs in lots of ejector hills. The air on the Irn Bru Revolution can also be fairly awsome when going backwards if you sit at the front.
mullenium force, it has to be the best, i would choose mf over ttd b/c ttd is too short, you dont have time to even notice how high you are, but on mf, it has a nice speeded lift. and if you havent been on it, just imagine a little 2-across aluminum car hurtiling down a hill over 300 feet in the air at near-vertical angles of discent.
I don't want to insult anyone or anything, but my friends call it Millinnium Forceless. Though I wouldn't go that far, I don't see what the hype about it is. If all you want in a coaster is speed or being up high for a couple of seconds, its teh best there is, but aside from teh first drop, there isnt much to it. After the drop, theres virtually no airtime on the camel hills, and the overbanks don't have much positive G compared to some. But beauty is in the eye of the beholder, and opinions are ones own.
My favorite coaster as of now is the Phoenix at Knoebels. Just so much airtime. Whooooweee. 17 moments of air on 17 hills, or something like that. The last run of 5 under 6 foot high hills in a row is easily the most fun 300 feet of track in the world. Each time you get violently thrown up against the lapbar(which is already pretty high off your lap), then just hung there, then you do it all over again on ever hill. The double up-double down element is amazing too, as teh ejector air and negative g is almost unmatched anywhere. The first 2 speed hills are more floater air, but honestly feel as fast as TTD, because of the tight structure closing around you.
But close behind Phoenix are Boulderdash, Raven, Grizzly east, Cornball Express(talk about a surprise), and Timbers. The first steel coaster falls in at about place # 16 on my list, and that coaster wuold be Phantom's revenge, followed by SROS@SFNE. But those dont come anywhere near the others I mentioned.