Depends really, on whether it's live or broadcast. Also depends on the level (high school/college/pro)
Baseball is by far my favorite live, although only at the professional level. Hockey would probably be a very close second if I actually got out to more games. NHL, college, and high school games are all quite fun. Football is ok live if you can sit in mid-level 50 yard line seats. I won't shell out $300 for Bears tickets, but NIU tickets are easy to get, and high school games are ok. Basketball is crappy to watch at all levels. Soccer is only fun to watch when children are playing.
The only sports that I like watching on tv are professional. I'll never waste my time with basketball or soccer. Hockey is a lot tougher to follow on tv because you get tunnel vision and cant see where a person is passing to. I like watching the White Sox on tv, but pretty much no other team. Most NFL games are great to watch on tv, and football would be my favorite sport to watch on broadcast. Although typically football broadcasters are the worst.