It just so happens that I had an 06 Jamis Diablo 2.0, and had a Travis on it as well. The travis was the TPC+, (not the intrinsic), and it handled just fine. I don't, however, know why you would want to go backwards from a triple to a single, or even a single 1.5. I would just keep the triple.
I'm pretty sure you are going to get the majority of replies to your thread to vote towards Marzocchi, and you'll hear Manipoo this, and Manipoo that, from people who haven't even tried out the fork, and are just from hear say, and not from actual experience... but don't cut manitou short just yet... If you like the way your triple feels, the single 180 feels the exact same, only your turning radius dramatically increases, and you can do half or full bar spins depending on your set up.... you might feel a difference as far as stiffness as well. There is a lot of argumentative controversy about the durability of these forks, but I beat the crap out of mine, and nothing has happened in over a half a year... who knows, maybe I'm just one of the lucky ones.
BUT, at the same time, I'm not going to lie to you. I, too was strapped on a budget at one time, which is why I chose the Travis over the 66. If I would have had the money for a 66, I would have bought one. The 66's are bad @$$, have more adjustments, are easier to tune, and are known for their durability. The only thing it doesn't completely have on the travis is stiffness; maybe due to it only having a 1 1/8 steeror instead of a 1.5 steeror, but the 66 is still pretty stiff none the less.
So if you can afford it, Go for the 66. But if you can't, don't feel bad about getting the Travis. I bought the Travis at first just as a temporary fork until I could get something better. Now after having it for a while, I see no need to change it to anything else...
Oh, and by the interview from Hayes at interbike: to put it short, Hayes made it VERY clear to everyone that they were going to fix all the silly'ness of the previous owners of Manitou... just food for thought.