Build a 5th level (or 6th level for non-humans) Sorcerer with 8 ranks in Knowledge (arcana), the Arcane Preparation feat, Cooperative Spell feat and any other Metamagic feat. Now take the Mage of the Arcane Order prestige class.
You pick your most useful combat spells for your Sorcerer's known spells. Since all your daily slots are spontaneous slots and are always 'unprepared', you can take a full-round action to drop a utility spell (assuming it's available in the pool) from the Spellpool into them at anytime. You gain the utmost in versatility, and become perhaps the best universal wizard available, while retaining combat capability.
The disadvantage is that, with this combination, the two feats required to meet the prerequisites for the prestige class, Arcane Preparation nd Cooperative Spell, are nearly useless. Is it worth it? Under most circumstances, I think so.