Agave tequilana is one of the more vibrantly blue Agaves with long slender leaves.  It will get about 4-5 feet tall and wide and has some pointed tips so be careful where you plant!  It iwll produce many little 'pups' at the base, and propigation of them is fairly easy.  Provide well-drained soils and full sun.  This Agave requires very little water and is suitable for xeriscape.  It's drought and deer tolerant.  Native to Jalisco, Mexico.  Hardy to 30 deg. F.