MattDest raises a crucial distinction. Irrespective of the value of "tailoring" the personal statement to specific schools, should one drop names? I'd say, in general, no. If you'd like to work with professors X and Y, and the rest of your application betrays that fact, the admissions committee will very, very, very likely know it. If the admissions committee doesn't know it, then reconsider whether you really know whether you'd like to work with X and Y.
Sometimes dropping names may harm an applicant. One runs the risks, most notably, of misstating a professor's interests and inciting jealous reactions from other faculty on the admissions committee.