99.9% of the time I run 4x 120 Bard skills and 120 Mage/Med. During spawning levels I run the Provoke Masteries, and use 2 EV's and Firehorn for killing stuff, with the odd Discord or Provoke thrown in at later levels to keep the heat off me. For the champion switch to Discord Mastery, Discord it, then use Despair & Tribulation set on it's weakest resist. Provoke if possible but prioritise keeping the Masteries active. Depending where you're spawning you can get some good Provokes (i.e. lost lands Parragon Greater Dragons vs Meph) but in general if there's a group they will end up killing any Provokes through lack of awareness.
I haven't been in game for a while but I think Doom is probably the best arena for a pure Bard, all of the rooms can be solod with Discord Masteries, and the DF can be solod with Provoke/Summons/Masteries.
If you're not at that level yet (soloing bosses) and are still on regular level 4-5 monsters (Blood Eles, Balrons, Ancient Wyrms, Shadow Wyrms) then anywhere where there is a lot of spawn is great. Unbound Energy Vortex's and the nearby Eles (can't remember name) are good, as you can get all 8 on the UEV plus Discord Masteries, plus Air Ele Summons, plus if you're a loon a Mage Weapon Heavy Xbow.
You can also consider having 120 Spellweaving in place of Peace, but it makes both your Provoke and Discord Masteries weaker, that would be effective throughout the fight, for a high burst of damage right at the end of the fight (where depending on how many are attacking it could be less worthwhile).