Eye of the Beholder (1999)

Psycho thrillers are always fun, but it's even more intense to see the unholy team-up of TWO crazy people - and thanks to Ewan McGregor and Ashley Judd's characters, that's exactly what we see here. Ewan plays Stephen Wilson, a surveillance expert called the Eye, that's assigned to keep track of assumed blackmailer Joanna. His wife and daughter left him years ago, so he has nothing better to do, but he soon learns that Joanna is far more than a blackmailer - she's a serial killer with a host of daddy issues, thanks to her own abandonment as a child. She seduces several men, including the ass-baring David Nerman and Michael Perron, before killing them. Stephen manages to fall in love with her, thanks to their strange father-daughter issues, and, well, you'll have to watch the rest for yourself.