Are wind deflectors worthwhile if you have no AC? Openning windows for fresh air makes radio unhearable.
Depends really. You still get increased wind noise, but it is quieter than with no deflectors, when the window is open. The deflectors themselves to introduce their own noise also, so remember that. But, from my smoking days, I always prefer to crack the window open, even just a little, so I find them useful personally. I wouldn't add them as a styling accessory, but I don't think they look bad, and they do serve a practical purpose.
If you don't drive with the window open usually, and you have AC, then there is probably no point in getting them though.