Been really enjoying this hobby for over 3 years now....studying, practicing,etc. I still have my original body and lenses and looking to upgrade a bit. I've got a 50d w/ a 10-22 f/3.5-4.5 and the 18-200 f/3.5-5.6. I'm planning on keeping the 50d and the 10-22, but it's time to move on from the 18-200 and replace it with a couple faster, sharper lenses.
I've pretty much decided to replace it with the canon 17-55 f/2.8 IS and the sigma 70-200 f/2.8 OS. Problem is, I'd like to go for one now but will likely wait a year or two before the other as we have some other family projects coming up. I don't really "specialize" in a particular area, just dabble all over....landscape, wildlife, family, etc. But one of the main reasons for wanting to upgrade is b/c I now have a nearly 2 yr old son and a new 3 month old son. I find myself really needing a faster glass for indoor fun and portriats. Also even in the outdoors my 2 yr old is VERY active and fast. I'm getting a bit too many throw-aways and missing some great stuff at certain times of the day.
Based on that, any recommendations on what should be first between the 17-55 or the 70-200? Keep in mind I could supplement the missing range with the 18-200 in the interim. Also, getting the 70-200 and also a 50 f/1.8 II would be an option for me at that price. I know I'm still missing the focal range but it would still be a bit wider and a lot faster indoors. Any help/thoughts???