[ChrisRabior]

As mentioned above, the 18-200 upgrade is more in terms of convenience. The 18-55 and 75-300 have that slight gap between 55 and 75, and I've yet to be disappointed with Sigma lenses.

Kinda flew off topic with the telephoto talk. I'm planning on going the route of the 70-200mm f/2.8. Not yet positive whether I'll do the canon f/4 and eventually up to f/2.8, or if I'll just go straight to sigma's f/2.8. With the awesome resale value of canon lenses, I have to think I'll get the f/4 and a 1.4 TC to complement it.

Back to my original question.. if you were looking to pick up either the OS or non-OS version of the 18-200, would the OS be that big of an upgrade? I guess I'm looking more for people's experience with stabilized lenses. Is it really a worthwhile function? Do any of you actually use it/swear by it? Just trying to get some help in deciding whether it's worth the extra bit to do OS.. but as it is $140 more, I certainly wouldn't mind saving that up for a super wide angle or my 70-200 goal if OS isn't that big of an upgrade.