The direct damage spells aren't even the big deal. A charging Barbarian can do more damage than your metamagicked orb spell, unless you concentrated your resources really hard on that as a Wizard.
But Glitterdust, Web, Grease, Stinking Cloud, to name low-level stuff, or their bigger Conjuration brothers Solid/Freezing/Acid Fog, Black Tentacles, Cloudkill, Wall of Stone, and of course Summon Monster X are a real pain in the ass. And most of these didn't allow SR in 3.0, either, if I recall rightly.