None of the 3.5 prestige classes have ever held my interest, but my tastes in 3.5 are questionable: I play light armored fighters, which means I tend to suck.
My ranger completed Tempest for the two-weapon benefits, and I currently have a scout early in Order of the Bow Initiate, which might as well be a five level class.¹ I'm far more interested in a swashbuckler conversion, or the upcoming Trickster to convert my beguiler to *Craft. Oh, and I thought the various dragon blood feats for sorcerers were cool, and it would have been awesome if Dragon Disciple was as cool as its concept, or at least rose above 'steaming pile' mechanically.
¹(If there's one thing I'd like to smack a 3.x designer for, it's 2 skill points a level for smacky uppy classes. Or for any class, really, but the whole "you hit hard so you don't need skills" theory is so stupid it hurts.)