Downwind Approaches
That's a tricky question actually. In common practice, all other risks being equal, take the approach into the wind. Your job as a pilot is mostly about risk management. A traffic pattern at an airport should never place you downwind just for the controllers convenience. You are accepting additional risk with no benefit.
The reason the question is tricky, though, is this. I advocate becoming skilled at downwind approaches. I actually think it should be part of the curriculum. Learn to recognize the signs of a downwind condition, (faster than normal closure rate, further aft cyclic position, changing power demands, etc.) and how to safely execute the approach or perform a go around. At some point, whether you're prepared or not, you'll find yourself in a downwind condition, even if you've read the wind perfectly just moments before. It's best to practice downwind approaches under controlled conditions and become proficient. If you don't feel comfortable doing this on your own, book some tiime with an instructor and practice approaches with the wind at various points around the azimuth. You'll make yourself a far more proficient pilot. Good luck