What carpet cleaning method works better?

Which carpet cleaning method works best, steam cleaning, (hot-water extraction) or the chemical dry-cleaning method? (like Chem-dry). Are there any other methods? which have you used and had good luck with. Which method works best on pet urine odors?

http://www.carpetprofessor.com/Reputable_Carpet_Cleaning_Care_Guide.htm

http://www.carpetprofessor.com/alans_best_carpet_cleaner_directory.htm

http://www.carpetprofessor.com/carpet_cleaning_promotion.htm