Originally Posted by kingsnake2
I actually want the 18-200mm lens because I love to travel.
Well I guess I have some learnin to do over Christmas break.
The EF-S 15-85 IS is an amazingly versatile lens.
It covers wide angle, which imho is vastly more important than tele for walk around/travel photos, allowing you to fit buildings, people, tight spaces etc in your frame.
The 85mm @ a crop camera is actually also a pretty handy short tele.
At the same time it is quite fast @ f/3.5-4.5, and the IS is pretty effective for available light (no flash) photos.
All in all the 15-85 is an excellent travel and all-around lens.
I know that most "young" photographers, are impressed by long tele lenses etc, but if you do a poll among D-SLR owners with 2-3 lenses, the vast majority of them will be using their tele-zooms (usually a 70-200 or a 70-300) in less than 10% of their shots. This has been the case in multiple photography forums I've been a member in, ranging from dpreview to fm and photo.net, to smaller regional forums and groups.
This is also the case for me, owning a 70-200 f/4 L and having "in the family" the ability to borrow the 70-200 2.8 I L, 70-200 f/4 L IS and 300mm f/4 L. Unless I go for bird shoots or visiting a Zoo, the lens of choice is the 17-55 IS, followed by my Sigma 50 1.4 for portraits.
If you have the money to drop on a 60D + 18-200, you can most likely afford to keep your Rebel and add a 15-85 IS and if you really need/want/got to have a tele-zoom, get the 70-200 f/4 L non IS, and be comfortable knowing that you own two of the best value for money lenses you can find regardless of system/mount in the market today - if not the best.
The 70-200 blows any wide-tele zoom.
EF-S 18-200 vs 70-200 f/4 L is like Ivy bridge vs. P4 here, no kidding (you can guess which is Ivy).
Virtually un-challenged by zoom lenses cheaper than $750-800, and beating some in the $1000 range (that might offer 2.8 maximum aperture tho). Still after your "honey moon" with it, I bet the 15-85 will rarely leave your body