The deck is stacked against the spellcaster who multiclasses in 3E D&D. The prime power balancer for casters is highest spell level castable. The prime power balancer for fighters is base attack bonus (BAB). The paladin5/fighter5 is as strong as a fighter10 -- both have the same BAB. The wizard5/cleric5 is weaker than the wizard10 or the cleric10 -- having more low-level spells per day does not compensate for being able to cast more potent spells.
An unbalanced multiclass combo offers greater options. For example, the sorcerer8/paladin2 is pretty sweet, with the charisma synergy, save bonuses, healing, weapon selection, and access to paladin wands. The cleric8/fighter2 is also a good option, especially with War and Strength domains. But for a true even-split multiclass, it does not work to the multiclassing PC's favor.
Realizing the disadvantages faced by multiclassed spell casters, the 3.5 version of the core rules attempted to offer a couple fixes as prestige classes. The Mystic Theurge, Eldritch Knight, and the Arcane Trickster are examples of this, for the cleric/wizard, the fighter/wizard, and the rogue/wizard, respectively. Compare the wizard10 to the wizard3/cleric3/MT4 -- essentially a wizard7/cleric7 -- a much better deal for the multiclassed PC.
If you do have your heart set on playing a battling mage, the evenly split fighter/bard trumps the fighter/wizard and the fighter/sorcerer. As I demonstrated in a previous screed, from levels 1 to 10, the bard beats or equals the wizard as a spell caster for most levels. Spells including Heroism and Rage are especially good for the bard with levels as a fighter (or ranger, etc.) An effective tactic is to spell up, then start Inspiring Courage, and fight while singing. The bard's better BAB, hit dice, and ability to cast spells in light armor with no chance of failure also mesh very well. Speaking of armor, mithril chain and a mithril buckler offer the best protection with no chance of error.
The evenly split rogue/bard also offers pretty good synergies -- especially in skills, where the two classes mostly overlap. Use Magic Device and other charisma-based skills work well for this combination. Suggestion is a prime spell here, as well as the Charm magics.
But I do not recommend a spell caster mix. The wizard/bard and the sorcerer/bard offer no advantage over a straight bard (despite the sorcerer/bard's charisma synergy), since the spell lists overlap. Combined with druid or cleric, the bard can wear armor and cast both arcane and divine spells, but as I mentioned above, casting more low-level spells does not compensate for missing out on high-level spells. The bard10/cleric10 is no match for the cleric 20 or the bard20. Unless you have a huge role play reason to do it (playing the follower of the god of music, perhaps), you will find this option to be an exercise in futility.
Similarly, prestige classes that stack with base classes to boost spell casting ability (like the Loremaster) are almost always poor choices for bards. The sorcerer, for example, basically gains nothing from adding sorcerer levels except improved spellcasting (and an improving familiar); the sorcerer/loremaster gets all the advantages of adding sorcerer levels (except for improving that familiar) plus loremaster adds. The bard/loremaster, on the other hand, loses too much: bardsong, bardic lore, good BAB, good reflex saves, etc. Granted, the loremaster gains 4 skill ranks per level, only two less than the bard, and has a decent skill list, including Perform and Use Magic Device, but that's still not as good as the straight bard. The loremaster add-ons do not make up for that. The same goes for the Mystic Theurge, the Arcane Trickster, the Eldritch Knight, etc.
But prestige classes that do not boost spell casting ability -- especially those that require spell casting ability -- are good choices for bards. The prime example is the bard/arcane archer. Most arcane archers are otherwise fighter/wizards -- and bards beat fighter/wizards at fighting, spell casting, or both, at just about every level. Add in casting spells in armor, and the bard wins pretty handily.
The bard/shadowdancer is also an interesting combination. The required Perform skill is not problem, and the role play synergies (music and dance) work nicely.
Then there are prestige classes that are designed for bards -- such as the Seeker of the Song and the Sublime Chord in WotC's "Complete Arcane" book -- but as with all non-core rules, your mileage may vary.
Edit [6 Dec 04]: The newest Order of the Stick Web comic features a multiclassing bard! The strip is really funny -- it pokes fun at mechanics vs. realism in taking a new class -- but I have to wonder ... why the heck would a bard want a level of wizard!?! Well, I guess you get a familiar, Scribe Scroll, and +2 on your Will saves. Eh, might be worth it. But OOTS is about being funny, not about power-gaming, of course!
Hey! I got some feedback [9 Dec 04]:
Just a nit-pick (since gamers like to do that):
The best armor for a bard in 3.5 (and I play one) is mithral breastplate + mithral buckler.
And here is my reply:
Thanks for your e-mail! You are officially the first person to spontaneously write to me since I started blogging last month. I hope you won't mind if I quote from your letter on my site.
Let's get to the heart of your nit-pick.
The DMG, page 284, says, "Spell failure chances for armors and shields made from mithril are decreased by 10%." A light shield or buckler normally has a 5% chance of failure. So a mithril light shield or buckler has a 0% chance of failure (you can't have a -5%). I totally agree with you there -- a mithril buckler is a fantastic choice for any arcane caster, including a bard.
The DMG, still page 284, also says, "Most mithril armors are one category lighter than normal for purposes of movement and other limitations (for example, whether a barbarian can use her fast movement ability while wearing the armor or not). Heavy armors are treated as medium, and medium armors are treated as light, but light armors are still treated as light." The reason the text says "Most" is because light mithril armors are still light.
Also check out the DMG, page 220. Under the entry for "Mithril Full Plate of Speed," the text says, "It is considered medium armor (see Mithril, page 284)."
The bard class description, page 28 in the PHB, says, "a bard can cast bard spells while wearing light armor without incurring the normal arcane spell failure chance." It goes on to say that medium and heavy armors still incur the normal spell failure chance.
On page 123 of the PHB, it says that the breastplate is pretty much the best kind of medium armor. Therefore a mithril breastplate is the best kind of light armor. Both mithril chain mail and mithril breastplate offer a +5 armor bonus to AC, but the breastplate offers a max dex bonus of +5 vs +4 for chainmail, and a skill penalty of -1 vs -2 for chainmail. The chainmail is 50 gp less expensive.
If your Dex is 19 or lower (or 15 or lower if you anticipate using Cat's Grace) and you do not ever use skills that incur an armor check penalty, the chainmail has a 50 gp advantage over the breastplate. 50 gp on an item that costs over 4,000 -- ha! The breastplate is the better choice.
Thanks for pointing that out, John!