We've got a unique melee weapon, a unique armor, lots of unique guns, we need a unique pair of boots! I know this suggestion popped up in the forums, but I couldn't find it, so I'm putting it right here.
I don't know where you'd find em, but just like the A. Armor or the L.S., you could get magic boots that do... I don't know, something magic.
Name suggestions, off the top of my head: Sandals of Icarus (not really Doomish, Greek Mythology), Boots of the Deep, Sandals of the Furies (a reference to greek myth but ALSO a reference to Dante's Inferno) Greaves of Chiron (again, greek myth and Dante's Inferno), or, lastly, and see the water suggestion for this, "Flippers of the Zora" (working title)
Personal opinion, I like "Sandals of the Furies."
Boot Functionality: Any number of things! They could, of course, do the same old thing: just be really powerful boots: 16/16 or 12/12.
They could teleport you once per level, at will, as if you always had at least one phase device in your posession, use it by using the boots like items.
They could increase your speed a little like the hellrunner trait
They could increase your speed a LOT once per level, as if you were at beserk speed, activated by "U"sing the boots as items.
They could fly, meaning you can't pick up items (if only activated once per level) or totally ignore acid, lava, and water (too overpowered, if you ask me, unless you activate it once per level.) Again, activate it like an item.
If you call them flippers of the zora, you could use that water some more-- maybe submerge yourself in the water, giving added damage reduction/reduced to hit? Or increased speed in the water? Something.
They could allow you to move very quietly, reducing the monsters ability to notice you, effectively lowering their site radius, or something.
HERE is an idea i REALLY like, please consider this:
The boots could allow you to "dash" in a straight line, up to a certain number of squares. This would be done as follows. You activate the boots like an item, or press some keybind button, and the targeting screen comes up. You can move the target so many spaces away from you, say, i don't know, 4 spaces, and then there's an animation of your little @ sign moving over to that square, really fast. No time/rounds would pass during this period. In effect, it's a controlled telport a short distance away, basically the "Controlled Blink" spell in Linley's Dungeon crawl but with a cooler animation. This could be REALLY REALLY powerful, so the DOWNside is that first and foremost, it's really short ranged, and either A. you could only do it once per level, or B. using this "dash" skill damages the boots AND can only be done every so often-like, once every "three minutes" or so. (I don't know how game rounds operate, so sue me.)
They could allow you to kick, Duke Nukem Style, so each melee attack you make WITHOUT a knife or chainsaw or LS adds knockback to your attack. (So, whenever you melee with a gun, or are unarmed, you knockback your enemy.) This one could be good or bad, or way too overpowered. Discuss, please!
Edit: Found the boots suggestion-- it's the very last one in this forum area.
Credits to the original forum thread, but I'll put it here too:
They could prevent knockback, stopping those pesky seargents from blasting you three spaces backwards into that hot lava!