Ace Hardware: hand tools, pipe valves, fasteners, abrasives, metal stock, and springs.
http://www.acehardware.com/

Do It Best Hardware: lumber, tools, screws
http://doitbest.com/main.aspx

Home Depot: Tools, packaged screws, bolts, metal stock
http://www.homedepot.com/

Lowe's: Tools, packaged screws, bolts, metal stock
http://www.lowes.com/

Orchard Supply and Garden
http://www.osh.com/

True Value Hardware
http://www.truevalue.com/