Most better players will use a 60 degree (or 58) for 95% of shots inside 80 yards. Getting the correct bounce and grind is critical, and there is no "best" grind... it's simply the one that fits your swing and the conditions in which you play.

If I was allowed only one wedge in my bag it would be a 54 degree.

I've got 3 different grinds for the 3 wedges I normally carry; 50 degree F grind; 54 degree S grind and 60 degree M grind.The 60 is primarily my bunker club, but I do use it for shots around the green, especially if I have to hit an approach to an elevated green.The 54 S is my go to club for most shots under 80 yds.

A wedge in the 54 to 56 degree range would seem to be the one that can cover the effective loft of +/- 4 degrees most effectively. Hence that would be the one I would choose if I could only have 1 wedge.

I too have 3 different grinds, 50.08F, 54.10D, 58.12M. For me the 54 is the most versatile, I use it for the 70 ish shots you asked about all the way in. The 54 is my go to chipping/pitching club from just about every lie imaginable. Really the 58 is a bunker only club, or if I really have to get the ball up quick. The 50 is more of a full swing club, or if I have a shot that I need to keep low and run a fair amount. My guess is if you practiced with each of them you could use whichever you like best, or use all of them for various shots.