I'm working on upgrading to a 10 gallon brew setup. I now have the burner (Thanks, Bill!) and a few half barrel Kegs. Before I brew my first batch in the half barrel I'd like an effective chiller. I currently have an immersion chiller that will chill my 5 gallon brews to pitching temp in 5 - 8 minutes (it's faster if I use an ice bath in addition to the chiller).
What kinds of chillers do you prefer, and for 10 gallon batches, are immersion chillers sufficient? If so, what length of copper do you use? It's a blank slate as to how I'm going to construct my brew setup so a little gravity isn't out of the question if a thermonater type device is worth the effort.