I've had little success with caster parties. There always comes a point where you face a monster with ridiculous SR and you wish your party had someone who could smash its face in.
Conjuration.
Or buff up and beat it up, if you're a cleric.
SR isn't the defense it claims to be.
Take for example Golems. Ever consider what happens when you cast Grease on the floor a golem's standing on?
This I heartily disagree with. I have seen people build fighters, rogues, and rangers who can do outrageous things. Casters tend to get the spotlight because their abilities are more flashy, for lack of a better word. It is just as impressive, though, when a fighter kills a chimera, moves on to cleave two minotaurs, and severely damage the evil cleric that summoned them.
You'd have to be very high level to do that, as you need Great Cleave as well as the ability to deal enough damage to one shot minotaurs.
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My Red Hand of Doom campaign last semester involved what was almost an all caster party. Paladin, Beguiler, Cloistered Cleric, Shapeshift Druid, and
James Mallory, Arcanist. Running out of spells was not a problem, as we had x2 the spell slots of the standard party. Skills were well covered by two 6+Int mod classes. Fighting was taken care of by the Paladin, Cleric and Druid, while the Beguiler and my sorcerer were often able to cripple the (sometimes very large and numerous) opponents that came up.
Funny story: we went off the campaign track for a bit and happened upon a goblin encampment. Long story short, we got into a battle and ended up killing nearly a hundred enemies (AoE blasting and control spells helped). Mostly zombies and orcs, but there was also a hill giant in the mix somewhere which exploded when the paladin used Spirited Charge on it.