I built what seems like a pretty effective martial bard character with the Spell Compendium and the Eberron core book. The key is maxing out your Inspire Courage result, with the Inspirational Boost spell and the Song of the Heart feat, which combine for an additional +2.
I built the character for a high-level game that my DM is going to run in a couple of months. The sourcebooks were pretty wide-open; let me look at see what I ended up using.
Dwarf Bard10/Fighter2
Feats:
C1: Battle Caster (Complete Arcane)
F1: Power Attack
C3: Force of Personality (Complete Adventurer)
F2: Cleave
C6: Song of the Heart (Eberron core book)
C9: Ironskin Chant (Complete Adventurer)
C12: Melodic Casting (Complete Mage)
Spells:
0th: Dancing Lights, Detect Magic, Mage Hand, Mending, Message, Prestidigitation
1st: Cure Light Wounds, Disguise Self, Improvisation (SC), Inspirational Boost (SC)
2nd: Glitterdust, Sonic Weapon (SC), Tactical Precision (SC), War Cry (SC)
3rd: Charm Monster, Fear, Haste, Sonic Shield (PHB2)
4th: Resonating Bolt (SC)
The character wears mithril full plate and wields a Crystal Echoblade, which lets him add half his bard level to damage rolls. With Inspire Courage going, he's getting +4 to attack and damage, and an additional +5 from the weapon. In combat, he'd start with Haste on the group, and preferably Improvisation, Sonic Weapon, and Sonic Shield on himself. Seems like he'd be pretty decent; I'm looking forward to trying it out.