Help Finding The Right GPU Please

So I often get computers very quickly and no hassle, but graphic cards I find are just hard for me to shop for. I know what to look for in a graphics card to the extent of someone who has recently learned about what to look for, and so I call the masters of graphics cards to assist me in choosing the right one for a starting-ish card, since my other pooped out. 

Keep in mind that you may always leave suggestions and your opinions to the ones posted on the original post as this thread goes along in time. I hope to one day get a $400+ GPU so I don't have to worry too much, but these will have to do for now. Baby steps. Haha.

Price Range: 100-200 United States Dollars

Lastly, I am almost certain that you can use Nvidia cards on AMD motherboards, but I want someone to verify that it is true before I purchase one.

Best card for your price range: AMD Radeon R9 270X. $200. Or find a 7870 GHz for $180. 

Also, Best Buy charges a lot more for a graphics card. Look on Newegg instead. 

What does the rest of your PC consist of?  for the $150-200, I agree with st33med that the HD 7870/R9 270/R9 270X will be good for that price range.