There are two versions of Incantatrix:
There's one where it gives you some bonus feats, and honestly isn't anything special.
Then there is the one in one of the Forgotten Realms books, which gives out free metamagic like candy. And lets you apply your metamagic to other people's spells. After they cast them.
The second one is the one usually discussed on optimization boards, since it's the cool one (and the absolutely broken one, but neither designation is mutually exclusive.)
What are you thinking of specializing in? Ultimate Magus is nifty, but I have to confess not having much experience playing with it.
As an interesting side-bit, one of the things dredged up recently is that Oriental Adventures lets Sorcerers cast off the Wu-Jen list, so if you have Oriental Adventures allowed (it is 3.0, but it had an update to 3.5 in one of the Dragon Mags, so I don't know where it stands in your allowed books listing), it definitely gives you some more versatility (Wu-Jen have some painfully awesome spells that don't show up on the Wizard list, so this is a definite step-up).
To clarify, the allowed settings are Dragonlance, Forgotten Realms, and Eberron, right? You aren't using Greyhawke (the implicit "basic" setting of 3.5) as one of them (or using Iron Kingdoms material, as cool as a lot of it is)?