Another lightweight/small-kit obsessor here (spend a year on the road with only a 40L backpack, and even that I thought was too big).
If it helps, here's my kit at the moment: 15 f/4, 43 f/1.9, 77 f/1.8, K-135 f/2.5, tamron 17-50 f/2.8 and I keep a DCR-150 in the bag for macros
Used to have a 31ltd instead of the 43, but i much prefer the 43 focal length, size and weight. But that's just how i roll, 31 is a great lens, but too big, bulky and expensive for my tastes so I traded it for the 43+tammy 17-50.
The tamron 17-50 serves dual duty. I use it as a walk around lens when i'm expecting quick snaps and lots of action. I used to walk around with a 31mm ltd, but I find that a zoom gives me a higher success rate when I'm just trying to catch things as I'm walking around. But when i've got more time to consider a shot I treat it as a 24mm prime (that just happens to have a zoom ring) to fill my gap between 15 and 43 . Around 24mm-28mm this lens is amazingly sharp, so sharp that I've yet to see a prime in that range with a real performance increase to justify carrying around an extra lens.
I just got the K-135 f/2.5 instead of the 55-300 like you mentioned. I loved the thought of 55-300 due to it's size and weight, but I was afraid of the drop in IQ compared to my other primes that I've gotten used to. I'm sooooo happy that I went with the K-135 f/2.5. It's just an awesome lens. I've never tested a 55-300, but from the 100% crops I've seen from it, my k-135 f/2.5 blows it out of the water in a reasonably small package.
I'm veeery happy with this setup. In fact it's the first time that I'm not dying to buy some other lenses (although one day I would like a DA* 200mm f/2.8)
Last edited by scathontiphat; 04-17-2011 at 02:42 PM.