Hi everyone, thanks again for your invaluable input. Based on what most of you have recommended, I think I've managed to narrow down my choices to the 18-200mm or the 15-85mm. Though I'm more inclined to 15-85mm due to the reviews regarding the good IQ, and USM, cause that is what I really want in my future travel lense.
It is true the 24-105 L does seem a little lacking for the wide angle portion, and will require a UWA lense to cover it. I think the main reason I am attracted to it is because of the L quality and resale value, and it may not be that practical for APS-C cameras, probably it'll be very front heavy or a body like 550D.
Was just wondering, I am seeing very few people reselling the 15-85mm on clubsnap, is it because it is a keeper lense, or is it because not many people got it yet? Some are quite happy with it (like limleong), but other than that I don't really hear much about it as compared to the other general purpose lense.
As for future consideration, I personally would buy a 70-200mm f4 IS lense to pair up with the 15-85mm. Do you guys think it'll be a good combo?