Balance between Fighters + Mages
I think balance can be ok without magic items.
However, it all depends on your GM and the adventures.
Fighters shine in an environment where you have multiple encounters in a day that last multiple rounds. They get to swing every round, and so long as they don't run out of hit points, their combat ability remains the same.
Wizards (under 3e D&D) shine in an environment where you have one or two combats a day, and they can unleash their big spells to decide the combat. If you have more than two big combats in a day, the wizards start running low on high level spells and take a back seat to the fighters. That back seat may also come up if a particular combat has an opponent that can't be affected by the wizard (SR, immune to magic/enchantment/fire, etc.)
Imagine a party with a 8th level wizard specialized in illusion. That 8th level wizard, in addition to his illusion spells, might also have memorized: confusion, Evard's Black Tentacles, suggestion, fly, haste, greater magic weapon, color spray, hyptnotic pattern, glitterdust, Fox's Cunning, Cat's Grace, etc. That might be sufficient spells to dominate two or more big combats in a single day. (spells based on what I remember from a game last weeK).
Personally, as a GM, I would enforce the component rules for spell casting in a game without magic items. i.e. the Wizard doesn't have a HHH anymore, so he can't draw his spell components as a free action, and I'd make the wizard spend a move equivalent or a full action pulling out his components (depending on where he keeps the components, belt or backpack).
Tom