My favorite TV shows are ones that I can relate to or represent something that I wish I had done or could do. I like Bones and NCIS and CSI because I used to be a science major and I am still interested in how science saves lives and solves crimes. I like How I met Your Mother because I have a group of friends just like them and it relates to me on a personal level and its hilarious. Then there are shows like Dexter that I watch because the stories are interesting and it makes me think about right versus wrong and is it really a black and white issue.
I think good tv is in the writing. A good concept can drown in bad writing. So whatever the niche market is for a show if they have good production and writing I will probably watch it. I am so sick of crap like The Hills and Jersey Shore. It's not reality it's a catastrophe.