I've been using natural minor scales myself. They sound pretty nice.
As for chord progressions, I-IV-V works pretty good, and it's commonly used in trance. I kind of like to do I-IV-V-IV in one measure, then I-IV-V-I on the following measure. Or you could do I-I-IV-V. I think a lot of trance also does I, then V from the octave below, then IV-IV, then back to I on the next measure. Have fun with that!