I own the T3 Tourmaline and I have had it for a few years now. I love it. I have really thick frizzy hair, the T3 dries it in no time, it is also powerful with out blowing your hair all over the place. I love it and would never go back. I don't have experience with the other types, but I HTH.
I have heard awesome things about the T3 Tourmaline and I want it!! It was named the best blow-dryer in InStyle's '08 Beauty Awards. It weighs less than a pound too!
I have the pink T3 overnight and I adore it. It's nice and small but very powerful and leaves my hair shiny. I never thought that using a nicer hair dryer would make such a difference in how my hair looks...but it really does.
pollyjean, I have the same Revlon that you have right now. I have curly hair that is difficult to straighten, for reference. I've bought the T3 and didn't think it was worth the price and ended up selling it on eBay. I bought the new "cheaper" pink T3 and thought that was the same as a drugstore dryer with the T3 name on it. The best one I've tried is the Elchim Classic 2001 which I bought a few months ago. I recently went to Tabatha Coffey (from Salon Takeover & Shear Genius) for a cut a couple of weeks ago and they actually use the Elchim dryer that I have. You can find it on Overstock for under $70.