The original 18-55mm did not have "IS".

来源: 于 2011-12-06 09:31:42 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

I am fairly sure 18-55mm IS came after Canon XTi.

I am not sure about your 18-200.  If it has "IS", then all the lenses on the list will not make a big difference.  However, if your 18-200 does not have "IS", then, an "IS" lens will make a big difference, especially on the long end.