Pardon the thread necromancy, but I want to say my input of my favorite armor to use on X.
I like using the Neutral Armor for X for both looks and abilities.
For the looks, the white boots look excellent, but would be better without the black line streaks. The mouth cover is alright, but could have improved if it was similar to Casshern's.
For the abilities, I like most of parts. I like these combinations:
Head parts H, Body Parts I, No Buster Parts, Foot Parts I. With these, I have X shoot huge buster shots in a very short amount of time. I can also use the high jump abilities in various situations. Here is an example from a video I uploaded in my current YouTube channel:
[spoiler]http://www.youtube.com/watch?v=XI86smfErbs[/spoiler]
Head parts I, Body Parts I, Buster Parts I, Foot Parts H, For this combination, I can use the power and defense of the I parts and the speed of Foot Parts H. It makes X a beast. I don't usually pair Buster Parts I with Head Parts H because I have more control of whether X uses a half-charged or a full-charged shot. Here is an example from a video I uploaded into my previous YouTube channel, although I still upload videos in this channel every now and then:
[spoiler]http://www.youtube.com/watch?v=lc-aV2EBu-U[/spoiler]