Both types of music will have a place in the game.
Fast paced music for encounters, slow ambient music for exploration and building.
Music while building could be a little bit more progressive, having more things going on, but remaining calm, while the music for for exploration would be better off being something mostly ambient.
Having dynamic music would be feasible with StarMade's sector system, every type of sector could have its own music, and the music would only change when entering a different type of sector from the one you're currently in, with a smooth fade.
I believe this will make up for a great and immersive experience once coupled with decent sound effects and a better looking GUI.
I've put some of my own concepts in this thread, they are pretty much in line with the above:
http://starmadedock.net/threads/archers-music-concepts-for-starmade.3719/