I love Time Team, particularly when they're doing neolithic or mediaval stuff. Not so keen whejn they're looking for a crashed Spitfire or something like that.
Walls are good but I like artefacts...I like to see things made out of metal or maybe bone. Human remains are always a good one. I'm always amazed that they managed to distinguish fragments of pottery from pebbles.
I also love the sketches that guy does to recreate ancient scenes...they should sell them as prints.
Does anyone remember that programme Meet the Ancestors. They went to a Saxon burial ground and dug up a load of skeletons then did DNA testing on some of the local residents and found matches proving the families had been there for generations. That kind of shit interests me.