Well in metal are used a lot of interesting scale modes...Some of them are

Locrian mode---i like to use it,used in death metal a lot and at heavy
Dorian mode
Phrygian--Steve Vai uses it a lot
Lydian
Mixolydian

Hm...I don't think this is a real scale, but D Eb F# G A Bb C D sounds kind of eastern-ish...

While I'm not much of a soloist, I've found this site useful for just playing around with scales.

http://www.all-guitar-chords.com/guitar_scales.php

Especially useful if you're wanting to figure out more Egyptian/Japanese/what-have-you sounds.