Well, it depends on what you want.
Personally I always pick the chords first, depending on what flavor I want from the solo.
Your chord progression can either lock you into one scale, or free you toward alot.
A powerchord consists of two notes, so it opens pretty many doors. However, you're right, they're quite boring.
Take a look at the Cmajor scale, it's a diatonic scale, meaning it has 7 notes.
When it has 7 notes, it will also have 7 degrees. Each of these degrees have their own chord.
So,again, Cmajor.
C D E F G A B.
A basic triad consists of the 1, 3 and 5th note of the degree. And degrees are put like this I-VII, or I, II, III, IV, V, VI and VII. You get the point.
So, the chords:
I - C E G
II - D F A
III - E G B
IV - F A C
V - G B D
VI - A C E
VII - B D F
So, obviously you can see that each degree has their set of notes, derived straight from the scale.
Let's talk about how this work:
You see, it's all about the intervals.
The first degree is obviously major, because we're in C major.
So:
I - Cmaj
II - Dmin
III - Emin
IV - Fmaj
V - Gmaj
VI - Amin
VII - Bdim
These chords, is the modal progression of Cionian.
However you can swap them just as you wish, aslong as the intervals remain the same.
So let's say you wanna make a chord progression in Ephrygian.
Let's break this down and use Ephryg as root instead, so you can see the connection.
Firstly we will have the E as a root. So:
Emin
Fmaj
Gmaj
Amin
Bdim
Cmaj
Dmin
So, I hope you can see that the chords come from scales, but how you choose your progression is usually by which scales you want to use.
However, let's say you want to play a melodic feely piece.
Lydian is a good mode for this!
As with phrygian, we do it the same way. We will use Lydian as a root. Let's use C lydian this time.
C lydian will be:
Cmaj
Dmaj
Emin
F#dim
Gmaj
Amin
Bmin
Again, this is the full progression.
Try this:
Cmaj7, Dmaj, Cmaj7, Dmaj etc.
And play C lydian over it.
This will give you an idea of how this works.
The reason I picked these two chords is because lydian's second degree, namedly another major chord, will go good together with the root, to make a nice lydian feely progression.
Anyway, this may be a bit more than you asked for, but it will hopefully give you some insight to the whole chord progression subject.
Learn the scales, know their degrees, know the chords of each degree, to each scale you want to use.
When you can do this, you can easily mix up major scales with exotic scales like harmonic minor, et cetera!
Hope this helps!
Edit:
and to add a quick reply to the question, to break past powerchords you need scale knowledge.
The majorscale consists of 7 degrees, and each have its pattern. Pick the 1 3 5th note of each pattern, and you'll automatically know all the 7 chords without even trying