I made a starter tonight so I can brew a hefeweizen on Sunday. Normally, I just let the pot of starter cool until it's cool (~2 hours). Tonight, I ran it under cold water and cooled it off in 15 minutes.
A couple of big differences. The clarity was far improved, there was a lot more hot break material, and the taste was cleaner.
Which got me thinking about wort chillers. Does the ability of to chill wort quickly make this huge of a difference? I've always thought of it as a luxury item that would substantially shorten my brew days, but wouldn't make my beer better... but tonight's experiment seems to be indicating otherwise!