I've used darn near everything in recent years in order to find "tire bliss". The bottom line is. It doesn't fully exist. Let me explain.
The michelins ride like a dream. Smooth, predictable. Even in the wet. However, anything resembling a sharp object will go right through. No matter how new they are. So,, then you try to find something more durable. With durability, comes compromise. Compromise will cost you that buttery smooth, yet super fast, feel.
I liked the responses for the Open Pave. This is a comfy (almost too much so) tire that you''ll be hard pressed to puncture under normal circumstances. However, you're going to go through more of these than just about everything else made. With the exception of maybe a veloflex or a challenge. They just aren't designed to last. And by not designed to last, I mean just that. They were never designed for a long lifespan. Smoothness, durability and speed come at the expense on longevity.
I had great luck last year with Vredesteins Tri comp Quattro. I got over 6,000k's on them and they're still quite rideable. Downsides being, Oversized alloy frame riders need not apply. They are some of the most unforgiving tires I've tried. Alot of people compare the ride to Conti's GP4000. Yeah, if you pumped the GP4000 up to 180psi and then filled them with cement. I'm sure then, they'd ride the same. I personally found the punishing ride worthwhile for the unreal durability and speed.
A great tire that most don't know about are the Gommitalia Calypsos. They can usually be found quite cheap and they're made the same way a Vittoria open corsa or a veloflex tire are made. The casing is made first, the rubber is glued on later. This makes for a much more compliant tire at high speed than a vulcanized tire such as a Maxxis or a Vredestein. They ride as smooth as the michelin. They wear quite well and have good puncture resistance. The sidewalls are the achiles heel of this tire. If you're on alot of gravel or really rough roads. Look elsewhere. The sidewalls cut too easily.
My current tire of choice are Vredestein Fortezza tri comps. Wicked fast tires with unreal cornering ability. Durability isn't as good as the Quattro, but the ride is alot smoother over rough surfaces.
For me, the Vreds are the cats ass. However, they aren't my recomendation for most people. The Conti GP4000 might be the best all around clincher ever made. It's not the fastest, or the toughest or the smoothest. Look at it like most three week races. The fastest sprinter never wins the overall. The best time trialist doesn't always win and the best climber doesn't always win. However, if a guy can time trial better than the climbers and climb better than the time trialers, he has a better chance of winning. The GP4000 isn't the fastest tire, but anything faster isn't durable. It's not the toughest tire, but anything tougher isn't fast enough. It's not the smoothest tire, but anything smoother again won't be as fast or as tough. I could recomend the GP4000 to 10 cyclist and have 9 very happy people. Try that with any other tire and you won't please half of them.
Abit of a hint. Most people are already aware of this. So this is just for the uneducated few. Latex tubes turn any tire into a much better tire. I've tried michelin and vittoria latex and can honestly say that the vittoria are head and shoulders above the michelin. Be aware though. They need to be properly inflated every ride whereas latex isn't air tight.