I'm currently using this [amazon.com]
Canon 18-200mm lens.
I rarely use the 105-200 range though. If I were to pick up this lens what would I be gaining for my investment? I'm not a professional. I typically take photos (mostly landscape type stuff) on vacations and have them wrapped to hang on the walls of our home. Would this be worth the upgrade?
Yes and no. Having used the 18-200, pretty much anything would be an upgrade over that lens for landscapes...and the 24-105 is a nice lens...but, there are much better options for you.
For $800, you could have the Tokina 11-16, Canon 10-22, or the Canon 17-55 lens, each of which would be a better lens that you would get better pictures from. The first two would open up a whole new world of wide-angle shots for you (the difference between 18mm and 10/11mm is HUGE). The 17-55 would mean less distortion and more resolution across the frame.
I'd suggest buying an ultra-wide (there are many that cover the range from 10mm on), and keeping your 18-200 for when you need more normal shots.
Last edited by preppyak; 07-31-2012 at 10:50 AM..