You can buy ceylon cinnamon from
www.penzeys.com or
www.thespicehouse.com - both have excellent quality. I have some cinnamon from penzey's right now that is likely cassia (it's titled 'Tung Hing' cinnamon that I love on different foods in place of sweeteners - the flavor is amazing. I'll get Ceylon the next time I'm there though.
Seriously, once you are used to fragrant, fresher spices from places like the above (their stores are so much fun to visit and the prices are
) then you'll pretty much ignore the so-called 'spices' sold in stores that have much less flavor and are plain OLD.