50's to 90's? Wow, that covers a lot.
My favorite old shows are I Love Lucy, The Honeymooners and The Twilight Zone. I used to watch those a lot with my dad.
My favorites shows as a tween/teen were Saved by the Bell, Blossom and My So-Called Life (my boyfriend's mother just bought me the series of MSCL on DVD...I was so ecstatic! lol).