I'd recommend Pitch Black Progress, it's almost as good as Holographic Universe. Their newer stuff after Christian Alvestam left is good, but not nearly up to the level of their previous quality.
You should, however, definitely check out Solution .45, an awesome melodeath band that Christian Alvestam formed after leaving Scar Symmetry. Their 2010 debut "For Aeons Past" is probably just as good as Holographic Universe, if not better.