Shadow-Walker (Unapproachable East) is notable in that it allows you to enter a +2 PrC without resorting to Totemist dips or Shape Soulmeld. It also gives you scaling SLAs for +1 LA. In a game with buyoff, it's pretty good. Even without, I'd probably consider it. Probably not good enough to use outside of a Shadowlord build, though.