Thanks for the help guys. That's a shame about Natalie Portman Too bad about Winona Ryder and the Olsen twins as well.

I'll only answer the ones I know for sure

Hilary Duff - PP/secretarials
Lindsay Lohan - secretarial inscriptions with sometimes autopenned autographs sometimes secretarials
Mark Kate and Ashley Olsen - nothing, rarely a secretarial
Winona Ryder - nothing
Robin Williams - secretarial via agent, possibly authentics VV
Kelly Clarkson
Natalie Portman - worst signer ever... nothing and bad IP too, also usually very rude
Julie Andrews - PP, lovely IP though
Miley Cyrus
Ashley Tisdale
Fred Dalton Thompson
Stephanie March
Jill Hennessy
Amy Grant

Natalie Portman - I don't think she signs VV let alone TTM.

She is VERY difficult to get IP. She refuses to sign.

Chrissy

Hilary Duff - PP/authentic
Lindsay Lohan - possibly a secretarial
Winona Ryder - I don't think she signs VV let alone TTM.
Robin Williams - Authentic
Kelly Clarkson - Authentic/PP
Natalie Portman - I don't think she signs VV let alone TTM.
Julie Andrews - Authentic/PP (from her fanclub)

Hope it helps!

I'm curious about a few actors and I'm wondering if they send authentics, only send authentics with when you send a photo, good VV signers, autopens, preprints, or secretarial. A couple of these people mentioned below are often on most wanted lists, leading me to believe they're not good signers, but I'd figure I'd check just in case.

Hilary Duff
Lindsay Lohan
Mark Kate and Ashley Olsen
Winona Ryder
Robin Williams
Kelly Clarkson
Natalie Portman
Julie Andrews
Miley Cyrus (I'm wondering that now if she's back from tour if she will start sending authentics (again?))
Ashley Tisdale
Fred Dalton Thompson
Stephanie March
Jill Hennessy
Amy Grant