Any car that a chick thinks is hot. Some have been mentioned already such as the Mazda Miata, VW Beetle, Mini, etc.

Another important factor is color! "Chicks" really seem to find white cars hot these days (and that includes the X5) so that makes those chick cars. [That being said, I do like the M3 in white but there's not really another car that I feel that same way about with that color].