Abjurer over Evoker
I also tend to go for the generalist wizard, but if I had to specialize because of the flavor or needs of a campaign, I'd pick Abjurer over Evoker any day.
Look at it this way. You can be a specialist in anything (Wizard by school, not PClasses and stuff) and get a bonus spell per level. The bonus spell has to be a school that you want to cast alot. Granted, Evoker and Transmuter are the 'high end', but you have to give up so many schools to get them. Take Abjurer - it's cheap. Use the bonus spell for an Abjuration and simply make sure you use one slot of each level for an Evocation and you'll feel like and Evoker (or same for Transmuter).
Why take Abjuration over some other 'cheaper' school? Look at Abjurer this way - you never want to be without them: Minor Globe/Globe, Dispel Magic/Greater Dispel, the list goes on. Really there are not many 'crappy' abjurations (unlike Necro and Div, or even Illusion if the campaign does not fit that style).
-Fletch!