I don't have a favorite, but I have some that I like enough to keep on my radar when the sales hit. Some have already been mentioned.

1. Michelin Pro 4. Not a bad thing to say about them. Really a great tire. Mine are 23s. They go and they are tough, in my experience.
2. Continental Grand Prix Classic 700x25 - No complaints, grip well, smooth, well made, and I like the dark sidewalls on some bikes, especially if the gum hoods are on the dark side.
3. Panaracer EVO SX Competition 700x25 - These feel more plush than other 25s. Really comfortable for a narrower tire. Discontinued, unfortunately. I'd buy again if rereleased.
4. Continental GP5000 700x25 - I only have 14 miles on these but was very, very impressed. Felt plush like the Panaracers, yet quicker somehow. Really excited to put some miles on these come spring.

I will say, though, after reading through all of the other posts here I really need to get my hands on some nice Vittorias.