#1
i know the major and minor scales and stuff like that, but i want to get more creative and learn the modes. I play mostly blues/rock/metal type stuff, but i'm gonna learn all the modes. what i want to know is what modes sound best with what styles of music. Also, what scales should I learn to play the classical sounding stuff like Randy Rhoads and Yngwie?
#2
For classical lines, try the harmonic and melodic minor scales.

Make sure you don't learn all the modes as fingerings, because modality is determined by the chord progression -- research the intervals that comprise certain modes and how they create certain moods. For example, Mixolydian is a blues-style mode, Aeolian sounds sad, and the best word I can use to describe the sound of Locrian would be sinister.
#5
the phrygian scale is great because you can make it sound Latin or dark angry rock. Mainly because the first two notes are a semi tone apart
#6
A lot of heavy rock uses the Aeolian and Phrygian modes and the b5 of the scale. When using the Aeolian scale, many bands replace the 5 chord with a major 5 chord, so E major in the key of A minor. Over that E chord, A harmonic minor would be appropriate. A lot of Randy's classical stuff somes from that mixture of Aeolian and Harmonic Minor. The "Mr. Crowley" solo uses this extensively.