If money wasn't an issue which chromakeying software is the most profesional/best? I've heard great things about Ultra but I got the impression that Ultimatte was way better but also way more expensive.
In my experience, there is no 'best' keyer out there. None of them will get you 100% of the way there 100% of the time. (Although, I think every compositor has a favorite keyer)
Here's a great article about the different types of keying and different solutions that have come up over the years: http://www.fxguide.com/article314.html
My brother has Ultra2 that he uses for editing. I've tried to use it but I tend to work with images sequences which Ultra can not import. In addition, it's severe limitation to screen sizes combine to make it practically useless for my purposes. Otherwise I liked it's ability.
well Raptor you could do it in MATLAB (which can easly support for sequences) for ultra geeky-ness (plus you can play around with using some advanced custom maths to do the keying):