Re: So the weakest PJ Harvey album is White Chalk
Funny, White Chalk is my favorite of hers, basically for the reason you mention: "It's her sounding like a ghost for the entirety of album." Her earlier stuff feels so buried under a sludgy sound that it's hard for the melodies to come through. Though again, I could stand to give some of them a closer listen.
I went back and relistened to "Legs" since you mentioned it as a favorite - I think I'm just not into the guitar playing enough, for whatever reason, to really like it.