I find that second pair very difficult. Best long songs from both bands (although: these days I might prefer Stygian over Dante). I guess I'll play them in a row to make up my mind.
edit:
Dante's Inferno is dark, evil, and has nice, fast rhythmic moments. It is very good in shaping an exciting atmosphere. In certain passages it gives me images of ancient eastern cultures. The keyboards and modus attribute to that. This song has a bigger "cool" factor.
However, the Nightwish song is more beautiful. It is more consistent. Most, if not all parts are very strong. The melodies, including the vocal lines, are very strong. And that's what's won me over.
So I went for Ghost Love Score. At some point I had goosebumps, and that is certainly something that should not be ignored while making this choice.
*votes like Knick and RTC*