It depends on the material, how accurate, how many, and how fast. There are many different ways to achieve that objective. For a few pieces of non hardened material, I usually use the band saw in vertical position. For hardened material, a cutoff wheel in the Dremel works well. For steel of questionable hardness, I will use a hack saw rather than risk damaging my band saw teeth.
I don't make final cuts with any of the above if I need accuracy better than .05". Errors associated with measuring, marking, and the cut stack up prevent reliable cutting to size.. I will cur oversized and face on the lathe or the mill if cutting flat stock.
If I have a number of pieces to cut, it is convenient to set up a carriage stop on the lathe and use the parting blade. For short pieces, I just use a spacer the same length as my part plus the width of my cutoff blade between the stop and the carriage. I advance the stock to stick out slightly past the cutoff blade positioned with the stop and spacer and face the stock. Then I remove the spacer, position the carriage against the stop, and cut off the piece. This is fast and will provide consistent lengths to .001". For longer pieces, a pin in the tail stock will provide a convenient stop. For longer pieces, a steady rest should be used and stock should not stick out past past the back end of the spindle by any significant amount to prevent whipping.