Lingering Song is a great feat. Lets your bard sing as its first action and then the effects will linger for, er, 8 rounds if I remember rightly. Which will be enough to last to the end of most combats. This frees your character up to do other stuff.
Other than that, it really depends on what sort of Bard you're going for. In the campaign I'm currently playing in we had a bard who was specialising in Enchantment magic (spell focus feat.) With his maxed and stat boosted charisma he could cast a 1st level Tashas Laughter with DC of 17? Very high DC anyway. Good spell to cast on big bad fighters as it's a Will save and completely incapacitates.
If you're going for a diplomacy or con artist Bard there's always skill focus in the relative skill.
Other music feats like Green Ear and Requiem (although I have a feeling they may be 3.0 so might want to check up) allow your bard to effect critters that are normally immune to Bardic music. (Plants and Undead respectively.)
If you an give a better idea of the sort of Bard your after I'm sure there's folks here can help.
Break a leg!
