I have the Williams set and a CM Pro set at home and use Wiha Soft Finish and Wera Kraftform Lasertips at work. The short answer is that I don't think you could go wrong with any of them (or many of the others suggested here). I guess if I was forced to choose, I would pick the Williams set with the Wihas a close second. The Weras aren't far behind though. I had bad luck with the CM Pro set, but that may be an aberration.
Williams - I like these as a garage set. The hard handles are easier to keep clean and the big squarish handles let me get a good amount of torque on them. The tips are very durable and the price is great.
Wiha SoftFinish - These are a bit more expensive. The handles are very comfortable, but also collect grease/grime. Wiha tips are great. A great overall set, but maybe not the best in a greasy garage.
Wera - Good price for a good set. The handles are nice, but not my favorite. They don't get quite as dirty as the Wihas. The Lasertips have an awesome fit. But that etching seems to wear quickly. Haven't mangled any yet, but I have my doubts asa to their durability vs. the Williams and Wihas. Nonetheless, a great set for the price.
Craftsman Pros - These are generally pretty highly regarded. I had bad luck with my set and two tips were ruined. Maybe a bad day at the factory when they were made. I warrantied those, but the set is relegated to the truck toolbag. Others have had better luck.