I think I'd go I'm Not Dead as first choice, I saw her live twice during that album and she totally sold it to me, the title track is immense. Then Fun House, Then Try This, Missundaztood and Can't Take Me Home.
I remember loving Missundaztood when I first got it, but of all the albums I think it is probably the one I don't listen to in full very often, some songs when I'm in the mood are amazing, like Gone To California, but when listening to the whole album it's kind of a stall on the album, same with Eventually. It's an epic song, she sounds great on it, but it's a song I listen to on it's own, not as part of the album.
Just remembered how amazing she sounds on Runaway from I'm Not Dead, another of my top P!nk songs, she has this way of really showing emotion through her songs, and you can actually feel her anger or upset as her songs progress, she's a bit like Gaga in the way she can absolutely sell a song on the final chorus with a big build up to it from the "Wasn't It you, Wasn't it You, Wasn't it you that Made me Run away..." it's just epic!