Back to "removing the Higgs == FTL travel": my first thought was: what'll keep all the newly massless particles together? I doubt the molecules would remain assembled as the speed of light.
Heat = random variations in kenetic energy (aka velocity) of atoms (not a great description, feel free to elaborate/correct me)
speed of light = (effectively) infinite velocity
so, from the perspective of an atom, traveling at the speed of light is a bit like being superheated, at least as far as interactions with other nearby atoms
Gravity is only one of 4 different forces, and is irrelevant on the atomic scale. Heck, it means significantly less even on the insect scale, where they could happily hold a blob of water the size of themselves without worrying about a cup. The theories that are predicting the Higgs particle, I think they keep all atomic forces intact without gravity.
But what happens when it crashes into something? Since its massless, then the thing it flies into should be entirely unaffected. Hell, wouldnt light break the darn thing apart?
Well, it depends on how bouncy you are. If you stick to the object, then it will absorb all of your energy into motion. That is what happens when we shoot light at a dark object.
If you are very bouncy, say 100% so, then you would fly back off of the object in teh opposite direction. The human structure would probably collapse like hitting a train (sucks to be that guy), but all your massless material would still exist. The object would actually gain twice your energy into motion, since it's sending you back the way you came. They can do this with high quality mirrors and light for space travel.
As for light breaking it apart, I... think you might be right. A massless object that still has the other fundamental forces would still absorb light, which would mean it absorbes the energy, and moves or changes accordingly. Light hits us now like a wet noodle might, but without mass we are basically wet noodles as well. Verdict? light-speed transportation would be a bitch.
I think that's what the theory guesses anyways, we'll find out more
if the higgs exists and
if we find it.