I play Lotus's UK 2fort server, which is in my favourites list. Mostly because i actually get good rates in it, but also because i like 2fort. The usual problem being that i get excellent ping from german and southern UK servers (9-15). Which actually turns out to perform a lot worse than having a ping of 60+ (due to how the servers and clients communicate resolved damage and deaths). I have a number of badwater servers in my favourites list as well. Other than that i run sunday gamedays so i get a good dosage of custom and cooperative play there.
If my favourites are full, which is 50% of the time, i just join a random server and don't fuss too much about it. I also play over at Playstuff.net's servers, they were kind enough to provide me with admin powers over there too, which is nice.