I tend to reserve my opinion of "hotness" for actors who exhibit not only sexiness but can also act and take on roles that I admire...with the exception of Angelina Jolie, who is so animal hot that it doesn't matter, lol, all of these actresses fit the bill.
And I love Michelle Pfeiffer, as well. She'd be on my list if she wasn't mentioned already.
Uma Thurman
Halle Berry
Angelina Jolie
Naomi Watts
Jennifer Connelly
Scarlet Johansson
Charlize Theron