If I were you, I would pick the class that's best suited to your play style. For example, pick bards if you're into supporting the group, monks if you enjoy very complex rotations, black mages for high burst damage etc.

If you want a true answer to your question, I found that for endgame, bards are probably the most sought after especially in coil. Their abilities such as manasong are unmatched and are almost essential in keeping the healers topped up with mana in pretty long fights such as twintania. Couple that with dps that has almost 100% uptime on the boss, and you have a very powerful class - even with the 2.1 'nerf.'
I personally picked black mage as my main, mostly because its a good class to start with for beginners, and I love how you can juggle between umbral ice and astral fire at lvl50 to achieve some pretty cool combos.
So yeah, try all the classes and just pick the one that you like the most. I don't think any class is terrible at lvl50 and all of them have their own strengths and weakness. And I highly doubt you'll be discriminated against because of your class choice... Unless you pick dragoon. Some of the people I've met have been teased quite a bit because they're a dragoon, but don't let that put you off.