I'm going to say TAR 4, some people don't seem to like it too much, but I didn't think it was all the bad. Not overly memorable, but I don't think it's one of the worst seasons
The route was pretty decent, Italy, France, Austria, Netherlands, India, Malaysia, Australia, and South Korea, lots of variety.
Some great tasks, the Fast Forward in the Netherlands being my favourite (nice leg in general), and the Seoul leg.
Some great moments, Kelly and Jon coming from nowhere in the second Malayasia leg and passing Millie and Chuck at the cave roadblock, Tian becoming the first women ever to do that bull riding task in India, 8 different teams winning a leg (partially due to the sheer amount of Fast Forwards, but still).
Good teams too, Kelly and Jon are one of my all-time favourite dating/engaged teams. Some of their quotes, especially towards the end (probably why the last 5 title quotes are their's). Jon and Al seemed like nice guys, Tian and Jaree and Monica and Sheree were fun to watch. Steve and Dave saying "Green Peace showed up and asked us to stop throwing whales off the tower" at the bungee jump in Austria.
Didn't care for the winners though (or a couple early eliminated teams), but I liked all the other top 9 teams at some point.
Again, not the best season, but not as bad as I feared it would be when I watched it.