Personally I have been spending a lot of time with Davinci Resolve of late. With a proper video card it is really an awesome program, and is certainly my current choice for color correction. It is fast and easy to use and does a very good job.
The other interest is SpeedGrade which I am learning, mainly because of it’s ability to roundtrip a grade to Premiere Pro and put it on clips as a single filter on each clip. A very cool feature, but the program needs some work before it can really compete with Resolve. First off it needs support for Black Magic cards instead of just AJA cards. If Premiere Pro can do it, Resolve needs to do it. And second it really does need curves. Curves are such a powerful color correction method that many have come to rely on, and not having them seems a huge failing. Other issues I have are it’s abilities with multitrack video are limited, and I have just gotten so used to nodal vs layer based correcting, though that is certainly not going to change. SpeedGrade is powerful and does work well with Premiere, but needs to get some updates to be able to really rival Davinci even with it’s ability export it’s grades as color correction filters into Premiere.