I prefer the original Quake to Doom as the best arcade style FPS. Doom is too limiting to me in it's movement and level design. Quake still has the abstract level design and that makes it the only 3d FPS that I've ever played to make true use of 3d space. It's almost like parkour as you're flinging yourself from surface to surface, doing rocket jumps, all while spinning in the air and destroying hordes of creatures. It's Doom but more agile.