He seems to have been a bit down after Claudia died and Louis left him, and also after that whole business with Akasha, but Lestat is at his best when he is out looking for new adventure or love affair. Despite the fact that he is killer, he really isn't an evil person. On the other hand, he's also an actor, so he figures that he might as well be the most evil creature possible, if he's to be evil at all. A character certainly bursting with charisma.
By the way...as a fan of Louis, I really must advocate for Louis's position as No.1 in Lestat's heart, no matter who else the lustful Lestat has affairs with along the way! ;)