Most things worth barding will require 120music/120barding skill. Peace is popular with brand new tamer for the purpose of taming tougher pets. IMO its not worth the skill investment, peace breaks to quickly using on targets your dealing damage to.
Discord is the most used, when the delay was corrected from 1 second the number of people using it dropped significantly. Even with slayer instrument and 120/120 it could still take 30 seconds or more to apply discord on 160 difficulty monsters so its most reliable on high hp monsters.
Provoke is probably the least used, I used it on a necro mage to farm some ML monsters when they first hit the server. Its a bit of a specialized skill, most people prefer to just hide behind a greater dragons as they can tank just about anything.
The most common bard build would be the disco/tamer
taming
lore
vet
magery
music
discord
If you hunt in a group a build like this could be viable.(dexxer)
120 Music
120 Discord/provoke
120 Weapon Skill
100 Tactics
100 Anatomy
60 Chiv
100 Spiritspeak
Im a advocate of wraith form, weapons are cheaper and single target dps is higher. But you could mix and match anatomy, spiritspeak, bushido, or necro to what ever fits your play style more.
Again if you hunt in a group this one could be viable.(mage)
120 Music
120 Discord/provoke
110 Magery
115 Eval
55 neco(+5 from bloodwood)
104 spiritspeak+10 from bloodwood)
96 spellweaving
discord + corpse and arcane empowerment + fb spam gives a large amount of dps.