If you can find one with a return policy (in case it's not for you), the Sigma 55-200 served me well for a while. It was a relative bargain at auction in May, but I haven't seen a sub-$100 price since then.
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When I decided the 55-300's reputation could not be ignored, I decided to save both grams and cash with a DAL version, and it's been excellent. In bright conditions it will even take my 1.5x TC for extra mileage - - but that's not something I need often. I'm sure that now and then I will miss the quick-shift focus, but since my old Alpha gear didn't have it I don't remember to miss it; the 16-45 has it though and that may cause me to reconsider.
If tests bear out its talent as well as its versatility, it might all go out the window for an 18-135 WR though...