The Dark Horse: Samplitude 64 bit. Crazy powerful. The plug-ins that it comes with are alone worth it. There's even an amazing convolution reverb that's amazing. PC only. Not cheap. But the best. Best sounding too. Don't let folks tell you that two DAWs eunning the same bit size and sampling freq will 'sound the same'. a) there's more than one way to write summing algorithms, eq algorithms, reverbs etc. b) Samplitude was one of the first to use large bit sizes for internal math. They led the industry, and still do.
Also: Samplitude is object oriented (again, they were the first). so, you can eq a track, do levels and fx on it etc., but you can also do all those things and much more (pans, fades, all the stuff you'd do on a track) on each object in a track. So, I just recorded 5 separate flute parts on a track, gave each one different fade ins/outs (different, totally adjustable fade curves of course), and affected their levels, while controlling overall levels at the track level (using touch-activated flying faders automation with my Mackie control), and then fine-tuning the level and fader automation in Latch mode.
Samplitude is much better known in Europe than here. The Hugely popular Vienna symphony sample package was mastered in Samplitude (it started as a mastering package, but is great for audo and midi tracking and mixing - but you can, of course, create a standard CD from within it, with CD text too). Many classical orchestras record with it, and many film scores too.
I recently did some 'session' work at home for a producer working in a major studio. He, the engineers, the artist, all were amazed at the sound quality (ISA828 premaps and Apogeee Rosetta 8 Converters are also responsible for that, as are my Genelec monitors: every piece counts).
Can't be beat, but it ain't cheap. I hear that a mac version is coming out soon, but I can't say if it's true.