Opinions Wanted: When is it OK to buy a knockoff?

I didn't know it at the time, but the Cotton Woven Chevron Throw ($50) I bought at Lands' End earlier this year was most likely a knockoff of Anthropologie's Icy Sorbet Throw (was $248, now $99.95), which I happened to see on the sale section of the website today.

Lands' End Version:Anthropologie Version:
Both are cotton with a pinkish chevron print. Both are 50" wide. The differences are slight: The Anthro version has "hand twisted" tassels and a slightly larger pattern. The Lands' End version is 12" longer. One is a little more orange, while the other is a little more red. All in all, pretty similar. I think I got a pretty good deal, don't you?

Sometimes I feel guilty buying knockoffs and cheating the original designer or artist of his/her due, so I leave the knockoffs on the shelf. (And let's face it, knockoffs are sometimes tacky, while original pieces can hold and even increase in value.) And sometimes I think hardcore DIYers shamelessly take other people's ideas without considering how it affects the original creator. I am not super adamant about this the way some people are, but I do think it's important to consider as a consumer.

In this case, with this cute but relatively unremarkable blanket, I had no idea the Anthro version existed--and for all I know, it could be a copy too. Had I known both existed, I still would've bought the cheaper blanket anyway... But if I were looking at say, an iconic piece of furniture, I'd save my pennies (and scour Craigslist) to buy an original.

In my opinion there are some things that should not be copied or reproduced... while other things are a little less sacred. I can't quite define where the line should be drawn, but it's there. What do you think? Do you have any limits when it comes to buying knockoffs or reproductions?