Dogfish Head Olde School is one of my favorite domestic barley wines.
Victory Old Horizontal is pretty good, and it just got discontinued, so...
Avery Hog Heaven is very good too.
JW Lees makes some good ones, but they are too expensive in my opinion.
What kind of commercial examples do you like? There are many (very) different barley wines out there. I hate to be Captain Obvious, but any judgement about the "best" barley wine is dependent upon the drinker.
My favorites are the Bourbon Barrel Barleywine from Central Waters, Third Coast Ale from Bell's and the GnarlyWine from Lagunitas. I like the SN Big Foot after a couple years in the basement. Some people prefer it young, with the strong hoppy flavors - to each his own.