Now some new ones (and some old ones not on the list above):

I post URIs and not hotlinks because they're harder for idiot webmasters to destroy, and they're easier for me to post.  If I didn't post a URI, that's because it wasn't easy to find one with Google.  I run a few searches and if I don't get satisfaction I move on.  Vendors can make products easier to find if they wish.  If it's a freebie I mark it as such, otherwise it's a commercial product.

Females:
Jessica Alba:
Thistledown http://www.daz3d.com/shop/thistledown-for-v4-a4/
Jess by Thwaites (Freebie)

Pamela Anderson:
Playmate 90 by Thwaites http://www.most-digital-creations.com/celebrity_victoria_4_3.htm

Emmanuelle Beart:
Warrior Maiden Tazi http://www.daz3d.com/shop/warrior-maiden-tazi

Hillary Duff:
Hilary V4 (Freebie) http://www.sharecg.com/v/46169/related/11/Poser/Hilary-for-V4/A4-UPDATED-1/22/2011

Kirsten Dunst:
SAV Eirene http://www.renderosity.com/mod/bcs/index.php?TopID=11219.102553.102560.254862.

Megan Fox
Andrea10 (Freebie) http://www.sharecg.com/v/39181/gallery/21/DAZ-Studio/Andrea-for-v4-base

Sarah Gellar:
Bluffy by William the Bloody (Freebie) http://www.2shared.com/file/ZCvSG54x/Bluffy_V4.html

Summer Glau:
River Tam (Freebie) http://www.sharecg.com/v/24894/gallery/11/Poser/River-Tam-morph

Paris Hilton:
Party-Goer for V4.2 by odnajdy http://www.renderosity.com/mod/bcs/party-goer-for-v4-2/93122

Lena Headey:
Electra http://www.renderosity.com/mod/bcs/index.php?ViewProduct=90575

Denise Richards
RM Marinda http://www.daz3d.com/shop/rm-marinda
RM Sasha http://www.runtimedna.com/RM-Sasha-for-V4.html
(A lot of RM's faces look like Denise so I just picked two lol)

Britney Spears:
Jamie 3.0 by LRP http://www.daz3d.com/shop/lr-s-jamie-3-0

Males:

Mel Gibson:
Mad for M4 by odnajdy http://www.renderosity.com/mod/bcs/mad-for-m4/84728

Jean Reno:
Leon for M4 by odnajdy http://www.renderosity.com/mod/bcs/leon-for-m4/87177

Will Smith:
Rapper for M4 by odnajdy http://www.renderosity.com/mod/bcs/rapper-for-m4/93533

Wesley Snipes:
Flame for M4 by odnajdy http://www.renderosity.com/mod/bcs/flame-for-m4/91834
Flame 2 Real for M4 by odnajdy http://www.renderosity.com/mod/bcs/flame-2-real-for-m4/92253

Jason Statham:
Driver for M4 by odnajdy  http://www.renderosity.com/mod/bcs/driver-for-m4/94302

Bruce Willis:
Red for M4 by odnajdy http://www.renderosity.com/mod/bcs/red-for-m4/88552