I'd recommend seeing The Keeper of Traken as an adult. Definitely one of the better stories IMHO. Sinister, harsh, desperate and with excellent acting, most especially form Anthony Ainley before he played the Master.

I did like The Caves of Androzani, but apart from the Doctor and Peri, the only character for whom I had any sympathy at all was Sharaz Jek, who has an awesome death scene.