I play a Necro 5 / Archmage 5 / Incantatrix 13 in one campaign. We play with a mix of 3.0 and 3.5 rules.
I have the following metamagic feats: Extend, Empower, Maximize, Widen, Quicken, Twin, Chain.
I use Twin the least (like never), Empower/Maximize a lot, Extend a few times (buffs and...