It took me a while to get into House, but I did start to enjoy it from about middle of season 2. After House drove a car through Cuddy's house you could tell they were getting desperate for plots, but the rot probably started earlier than that when Cameron and Chase left and came back and left and you get the idea. Last couple of years have been a bit pathetic to be honest.
I mentioned earlier that my favourite was Boston Legal, but there's a ton of other memorable shows I loved to watch. 3rd Rock from the Sun was a gem, along with Becker and as someone mentioned earlier Frasier. I was too young for Cheers though.
I still like CSI & NCIS (originals only) and the Law and Order franchise was great but has run its course (how many ways can you murder someone, seriously). SVU can be heartbreaking at times, some very intense themes and storylines in that one.
Some classics come out of the BBC. The Thick of It is simply brilliant.