Database design : what is the best data type should I use for different sorts of data?

you got to check this links;

http://www.slideshare.net/ronaldbradford/top-20-design-tips-for-mysql-data-architects-presentation

http://www.wsi-ebizsolutions.biz/blog/optimal-mysql-data-types/2010/01/

http://www.developwebsites.net/choose-optimal-mysql-data-type/

http://help.scibit.com/Mascon/masconMySQL_Field_Types.html

http://articles.techrepublic.com.com/5100-10878_11-5980073.html