Just add cold water?

I keep hearing people talk about wort chillers, to cool it down as fast as possible (I assume to help prevent infection, and help clarifying). When I made my batch of beer, my boil was about 2.5 gallons, I then added another 2.5 gallons of cold water to bring the temp down. Is there something wrong with this method? Is a wort chiller mainly used for batches that have a 5 gallon boil, which doesn't need any more water added?

-Tyler

When doing all grain and full boils, you dont have the option to add water to cool, hence AG brewers use chillers.

You might be surprised but adding 50% cold water doesn't really get the temp down where you want it. Better to chill the hot wort in ice water, then add the cold.

Nurmey's right. On my partial boil brews, I chill in the sink down to about 90 and then use fridge-chilled water to get it the rest of the way down. Works like a charm, but the water wouldn't work as well to bring it from boiling down to pitching temps. I like to get right down to 60 when I pitch. 10-20 minutes in the sink plus cold top up water does that for me.