#1
So if I'm soloing over a power chord riff, and I want to throw in an arpeggio lick, which arpeggios would I use? Would I go with the normal order (ie. Major for the I power chord), or would I be able to do either major or minor, since they both share the root and fifth?
#2
well you could sweep pick what ever power chord is being played, if its a G5 then sweep a G5 an octave higher
#3
You gotta find out what key the song is in first.

If it's in A major and the chord is F#5 for example, then you would use a minor lick.

So yeah the normal order works........
#4
^ i think something like this depends on the riff. if its just 4 5th type chords (ie E5) chords in standard 4/4 time as example then yes, i would just essentially arpeggiate the full triad of the chord (or if its triads i might arpeggiate 4 or 5 notes extensions that fit and lead into the next chord) . NOW if its an actual riff that has a constant motion i would probably try to arpeggiate several chords in contrast to the movement to create a counter melody.
#5
This applies to a power chord PROGRESSION (ie a measure of E5 then a measure of C5 then 2 measures of D5). If it is simply a riff based on power chords, such as Fig 1.873, your best bet would be, well, I'll explain it after Fig 1.873

Quote by Spamwise
So if I'm soloing over a power chord riff, and I want to throw in an arpeggio lick, which arpeggios would I use?
Find the key and then arpegiate the full chords. For the above progression, you would arpegiate Em, C, and D. You can get whacky with all kinds of extensions and odd notes. For instance, you could play (I have no idea what this will sound like) Em9, Cmaj7, Dsus2.

Quote by Spamwise
Would I go with the normal order (ie. Major for the I power chord), or would I be able to do either major or minor, since they both share the root and fifth?
You could mess around with that. There's no reason you couldn't play (again, I have no idea what this sounds like) E, Cm, Dm over that first progression. Since you are not in key, this will be harder to do and much easier to sound terrible. While you can get amazing sounds by going out of key, you can also get great sounds by staying in key. While I don’t mean to dissuade you from experimenting, sometimes, KISSing is the best way to go.

FIG 1.873

A---5---7---5---4----------
E-0-3-0-5-0-3-0-2----------------


If you want to play over that, I suggest finding the key, in this case E minor, and then going from there, playing E minor arpeggios with various additions.