Take a sample playlist of mine http://grooveshark.com/playlist/Trance/63694608
Skrillex and dubstep in general typically has a lower BPM than Trance. Skrillex usually works in the 120s, whereas trance is usually in the 130s-140s. You seem to be lumping trance and ambient together; however, they're quite different! I would argue that trance typically has more complex melodies than dubstep, which focuses more on tambre variations (ie crazy bass distortion). If you want to hear a cool trance track with high BPM and a nice complex melody, check out Duke Can't Come Home by Oza: http://www.youtube.com/watch?v=BA9If-QkXQk As with all electronic music, you kind of have to sit through the first 32 bars or so for it to get to the good part; these parts of songs are really only there so that DJs can mix them together more easily.