Department stores. Thrift stores are good for the occasional find -- sometimes you can make really good finds, even designer brands -- but I would never make the thrift store my primary source of clothing. I like Nordstrom, Kohl's, JCPenney, and even Target. Sometimes Express Men, but only for nicer things.
I shop at both. I shop in most clearance racks because usually there is some pretty good stuff in there! And I love to go to thrift stores and shop as well. I think there is often a stigma attached to people who shop at thrift stores.
When I was in high school, I would often shop at thrift stores (because I had little money). A friend of mine got angry one day and told me that I was taking things away from poor people because I was shopping at the local thrift store. Even though the local thrift store operates so they can fund a food bank and clothing drive for those less fortunate.
I think a lot of the opinions or stereotypes people place on thrift store shoppers is misguided.
I'm a big lover of antiques, and I love buying decorative stuff for my home. I also love finding cool accessories and one of a kind pieces. I have had a lot of luck thrifting over the years.
I also find clearance racks to be great too. Especially at the end of the season. I recently just purchased some things from a clearance rack. I got a few maxi skirts that were nice colours for the summer\fall season. They were on sale because they were summer stuff, I only paid 10 bucks for them. and they had the same skirt selling for 16 in the regular clothing section. Sometimes it helps to look around the store. Similar stuff is sometimes less expensive.
I buy quite a lot of clothes in charity shops (second hand shops/thrift) and I buy clothes online and occasionally in the store. I don't get why everyone wants to wear the same clothes though, like people all shopping in the same stores... buying the same dress and shirt and all looking like good little citizens... I don't get it but oh well.