There will be no more 120 Hz 16:10 monitors because todays games are made for 16:9 so it would be very strange to use any other aspect ratio for gaming than 16:9. Most gamers want 16:9.
/me channels his inner troll
Actually, what PC gamers really want is 16:3 (5760x1080) or 15:8 (3600x1200), since that's the future of PC gaming. Console gamers meanwhile are contempt with playing games at 1280x720 on 1920x1080 screens, often times at even lower resolution than that.
/exhale
Truth be told, games could be coded to favor any aspect ratio, it's pretty arbitrary... And many many games adjust it to some degree or let you adjust it, otherwise things like Eyefinity wouldn't work. So there's really no reason to lock yourself into anything, even tho FOV settings might often favor 16:9 by default (slightly) due to console-itis.