+1
I've never found it to matter much either way. There are enough good spells among whatever schools you have left to be awesome.
Two semi-related notes. First, I tend to build my spellcasters with a theme. That's the way I've approached it for the last several years as it tends to give them more character and, frankly, makes it easier for me to build as it gives me a heuristic for pruning the massive number of spells in D&D. Specialization is one way to do this, though it usually doesn't work out great. Illusion, Transmutation, and Enchantment are pretty thematically linked, but the other schools less so. And, Enchantment mostly consists of a bunch of spells that do essentially the same thing.
Second, in a lot of ways the conceptual space taken up by the specialist Wizard overlaps with the Sorcerer and other, more recent spellcasters (Dread Necromancer, Beguiler, etc.).