Living in South Florida, the LYS are pretty short on wool yarns. I visited three today, and one carried a small selection of merino, another had a few skeins of Plymouth Galway, and the last doesn't carry wool of any kind (even blends). I want to use Outback Wool and Ecological Wool and all these other cool wools I read about. So buying online is the only option for some of us.
The yarn from Holy Sheep Yarns is very sturdy and durable; it knits up nicely.
Fabriconnection has choices: Bartletts 2- and 3-plys, and a 2-ply that is a little bulkier and sometimes bulky but amazingly soft. That yarn is my current favorite.
I've found the LTK yarn to be a bit rough at first, but after washing and lanolizing, the roughness goes away.
I've purchased yarn from these places, too, but I haven't rec'd all of my orders yet:
Beaverslide Dry Goods
St. Peter Woolen Mill
I've read recommendations for these stores:
Have fun looking!