The best Batman was Michael Keaton. The 1989 film was outstanding (Jack Nicholson and Kim Basinger) and the 1992 film was very good (with Danny DeVito and Michelle Pfeiffer)
Honorable mention to Adam West and Burt Ward (as Robin) in the TV series.
Funny story about Burt Ward's screen test and audition.
On auditioning for Batman (1966): "To be perfectly honest, I didn't even know what I was trying out for. The producers didn't tell me. I remember that I went in for my screen test and two guys pulled off my pants and pulled on these leotards. I was afraid I was auditioning for a porno flick."