So a power chord only has the root and 5th in it which leaves all the coloration to you and whoever has the melody. This gives you a whole lot of control over how the song sounds.
However the chords, in arrangement, imply qualities.
Of course you have artistic license and you should do what sounds best, and this is only assuming diatonic harmony without key changes.
Using your charts:
E5 - G5 - A5 - C5- B5 - E5
or written based on their scale numbers
I - III - IV - VI - V - I
E is the starting chord/tonal center/resolving chord (the B to E at the end there is a V - I which is a common cadence or resolution/tension release) so its safe to assume we are in the key of E something (in this case minor, which I'll explain in a second)
Okay so the G and the C are the give aways that we are in a minor key, because they are minor, if the key was major they G would be a G# and the C would be a C#
E major = E, F#, G#, A, B, C#, D#
E minor = E, F#, G, A, B, C, D
So applying diatonic harmony your chords are really...
Emin | Gmaj | Amin | Cmaj | Bmin | Emin
or
i - III - iv - VI - v - i
This is because in a minor key the chords are:
i=minor
I=major
*=diminished (I dunno how to make that keyboard character)
i | ii* | III | iv | v | VI | VII
for major it would be:
I | ii | iii | IV | V | iv | iv*
If this is confusing remember that A is the relative minor of C and just like C it has no sharps or flats, the relative major of E minor is G, which also only has one sharp (F#). The pattern revolves see
http://files.meetup.com/227762/Circl...hs%20wheel.gif
Remember this is all based on diatonic harmony and in the end its up to what you feel sounds the best...you have artistic license.
As far as walking goes that's a whole thread/DVD/book in and of itself (and something I need to practice) but from what I understand most walking lines consist of chord tones, then scale tones, then passing/leading tones, each to fulfill a certain roll. So if the chord was a Emin and you want to walk it to G then something like E, B, A, G# would work. The E is the root and should start the bar in most cases, the B is the 5th which is a safe chord tone to move too, the A is a scale tone, and the G# is a passing tone that is out of key except it leads you right into the G which is next chord....the hard part is improvising them, crazy jazz musicians.