Mostly the new series', I've only seen a couple from the episodes but it is still wonderful. The 4th season (with david tennant and catherine tate) just finished over here in Australia, and it was pretty cool. I don't know when you americans get it, because i dont want to give away to much for upcoming episodes which you haven't seen.

Just let me say, any episode written by Steven Moffat will be and is wonderful.

i thoroughly enjoyed the last episode. just epic. now i cant wait to see who the new companion will be