Pro Tools may be the industry standard, but that certainly doesn't mean it's the best. In my opinion, it's getting left in the dust by pretty much every other major DAW brand. Cakewalk has been my DAW of choice for a long, long time, so I'm biased. I think it's the best. Every DAW has its strengths and weaknesses, but I think Cakewalk offers the most balanced set of features.
I believe the new industry standard for studios is likely to be StudioOne. I know a lot of engineers have switched, and only go back to ProTools when a client demands it. It has several things going for it that make it excel in a studio environment. I personally appreciate the slick project manager for mastering.
Cubase still seems to be the most popular choice for composers. I think that's due to its numerous MIDI features, excellent score editor, and of course sheer reputation.
But for me, Cakewalk still beats them all. That's a pretty audacious claim, but I don't make it lightly. While it may lack the project manager in Studio One, most people still do their mastering outside the DAW anyway. And although the score editor isn't nearly as full-featured as Cubase, it's adequate, and I can still export/import to/from my choice of notation software. In almost every way, I find Cakewalk to offer the best of both worlds. It's got a great workflow, good console, easy-to-access tools, flexible workspace, and creative "vibe". A lot of that may stem from familiarity. But I think it's more than that.