In addition to Dean and Teri...
Michael T. Weiss and Andrea Parker from
The Pretender. Their chemistry was so good that you noticed it even though they were rarely in the same scene together
. Actually, all the actors/actresses on this show had good chemistry with each other.
Also, Patrick MacNee and Diana Rigg from
The Avengers. I think they epitomize the phrase "on screen chemistry."
The whole original cast from
Stargate SG-1 (Richard Dean Anderson, Amanda Tapping, Michael Shanks and Christopher Judge).
Special mention goes to the chemistry between RDA and AT (because, I'll admit it, I'm a J/S shipper):
And Ben Browder and Claudia Black from
Farscape. They teamed up again in SG1 but I didn't enjoy their interaction as much, mainly because Vala just annoyed the heck out of me for the most part.
ETA: This post is worthless without pictures.