I think striving for balance is a good thing. But balance does not mean to me that classes are equal in ever situation. There are times that someone gets to shine and others are just supporting them.
Whenever I play a magic user I never feel like the rest are my henchmen I am very aware that they can make it without me but I can't without them.
I play high level fighters in 3E and I never felt that I was not as good as the magic users. I was swinging my sword 4 times and because of the feats I had a crit was a 15 and 90% of the time I confirmed it. I would wade through the battlefield leaving destruction in my wake it was really awesome. Sure the magic users may have been taking care of the enemy casters but if it wasn't for me taking care of the BBEG men they would have swarmed the wizard and killed him.
Yes there should be balance in the game but the DM also needs to be able to balance encounters if he doesn't then it realy won't matter how balanced the classes are it will not be fun for someone.
First, no one is saying all characters should be equal in all situations. That's just silly. What we are saying is that they should be able to contribute equally - something the 3.5 Fighter just can't do.
Also, it sounds to me like you and the players in your group aren't playing Wizards to their full capability - it sounds like you're not even particularly using all the tools they have available to them in the PHB, nevermind all 3.5's splatbooks. Do the Wizards in your group utilize Scribe Scroll and Craft Wondrous Item to break past their spells per day limitations? Do they utilize Save-or-Die or Save-or-Suck spells which can effectively end combats before they've started? Do they utilize utility spells that allow them to steal other players' niches?
If not, then you're very lucky to have such a well-behaved group to not play the Wizard class as its written. Though you have to realize that its not really fair to argue about the Wizard class as your group has specifically neutered it (whether intentionally or not) rather than as it is in all its horrific, unbalanced, as-written glory.