Primary and Tesco. Because I buy barely any of my own clothes, though I'd like to, and that happens to be where my mum goes.
Macy's men's, Nordstrom, H&M, American Eagle, Aeropostale... My personal favorite brands are Lacoste and Tommy Hilfiger
Hm...I buy clothes from Club Monaco, J. Crew, and Anthropologie. If I need some solid shirts and sweaters, I'll go to Uniqlo. If I'm spoiling myself, I shop Helmut Lang.
Charity shops mostly, because you never know what you're going to find. The other day I got a badass jacket (yes that's right, it's cool enough to warrant a UK person using American slang!) that's like a brown leatherette with pouch pockets, all I need now is a hat and a whip and I'm Indiana Jones!
Brooks Brothers (during their sales), Polo (usually from Macy's), Vineyard Vines, Last Call Neiman Marcus (I like their ties and dress shirts), Target ( for underwear and undershirts). I also get khakis and polo shirts from a company called Southern Tide. Sometimes I'll find good stuff at TJ Maxx or Stein Mart. Outlets are another good source of clothing. I almost always try to get good quality clothing on sale, such as end-of-season clearances. I don't usually wear clothing that's "fashionable" (e.g. joggers), so it will still look good years from now.
H&M, Forever 21 and Garage are my favourite stores (although I think they only have Garage in Canada)
clothes and shopping for them are depressing... target, h&m, forever 21, modcloth, sites i find from modcloth w/o the dumb mark-up, american eagle, vans store, zumiez, jcpenneys, macys, old navy, kohls, ross....... bits n pieces from everywhere and it all sucks if there were a uniqlo here i would go there a lot becasue i still have some shit from the time i went to the one in new york and it is very solid as a store
Target? I mean, honestly it's that or the occasional department store. Used to do a lot of thrift store shopping when I was first coming out of the closet.
Majority of my clothes are from Forever 21 and Target haha but otherwise I'll just browse random stores and get what looks good (provided it isn't horrifically expensive).
For male clothes, usually online at LL Bean, Lands' End, Eastern Mountain Sports, REI, Campmor or Sierra Trading Company. Sometimes department stores or TJ Maxx. For female clothes, online vintage, thrift and CD shops...