I have started sorting metal tubing by length. I found that I kept on having longer tubes in the way of shorter tubes, and what not, so for me this makes sense.
Pieces shorter than 1' go in drawers/bins.
Pieces 1'-3' get placed under my workbench (work bench is just over 3' deep, so the pieces don't stick out).
Pieces longer than 3' I currently just have on the floor or leaning up against the wall, but I will be building a rack of sorts to keep them. I get tubing cut to 10' lengths from the local metal shop, so USUALLY the longest pieces that I have are 10', unless there's a project that needs a piece longer, then I won't have it cut.