Also, all of the black blade abilities other than Life Drinker are either worthless, way too situational to matter enough, or "familiar does it, too." I could break them all down for you, but the categorizations should be pretty obvious...
Energy Attunement is OK and usable most days (it bypasses all forms of damage reduction if you know an element the target doesn't resist, and your an int based class with the 2 of the big 4 that covers most of the enemies with the non-obvious energy resistance so you should). Rest are pretty meh though, and most of your damage is coming off spells anyways.
edit: Went through the SRD just to make sure: The only first party undead resistant or immune to fire and not obviously on fire is the Bodak, Fallen, Fext, Gholdako, Ghul, Juju Zomie, Nemhain and Tzitzimitl (which is made of rock), less than 10 for one of the most common monster type (and lots of the remaining take extra damage from fire).