If you are hand holding and shooting street scenes, the best choice is Delta 400. HP5+ is a good second choice. Both are better than Tri-X. TMY is the sharpest and finest grained of the 400 class films, but it's quite contrasty and has a very steep toe, which means you'll often loose important shadow detail. It's also slower, by at least 1/3 stop, than Delta 400 and HP5+.(posted 8249 days ago)Why not two films? A 400 speed for handheld and a 100 speed for contemplative work. Any of the 100 speed films would be a good choice: FP4+, Delta 100, TMX or Acros. They all have their particular strengths and signature look, but they all offer excellent image quality.
In any case, if you must choose one, Delta 400 is it.