(Of course, also realizing that your potential employee or partner should be evaluating you in the same way.)
A) Compatible personality - someone with whom you enjoy working
B) Deep knowledge in whatever platform you're using
C) Broad knowledge in a computing topics; familiarity with other languages and platforms; experience solving problems in diverse computing environments
D) Subject matter expert in the domain you're working on - accounting, medicine, education, industry, public relations, etc.
E) Enthusiasm
F) Curiosity
G) Education
H) Logistics - person lives near you or is willing and able to relocate
I) Stability - can the candidate live with his or her means during tough times?
J) History of completing things
K) Communicates well
L) Polite
(not listed in any order)