Gel / Light filter for Canon 580ex? What do you use?

What kind of gels / filter kit do you use for your Canon 580EX? Canon provide a filter set up + gel for the latest flash but I have hard time finding filter kits for Canon 580EX flashes... There are some in the market (Rosco, etc.) but they seem to be poor quality...

What kind of gel do you use for your 580EX? Can you recommend a setup?

Thanks!