I just got back from Zermatt and I wanted to update my own thread with my experience concerning the ski pass and the single or return ride tickets.
First off, I am disappointed by the couple of "expert" responders on this thread as they did not clarify the difference of the tickets.
To put it succinctly for anyone else in the future reading this thread, the single and return ticket (found here: https://www.matterhornparadise.ch/en/winter/tickets-skipasses/single-ride-tickets/single-ride-tickets-new) is for sightseers or skiers/snowboarders looking for a quick run. It only applies to specific locations mentioned on the webpage.
The ski pass (found here: https://www.matterhornparadise.ch/en/winter/tickets-skipasses/skipasses-winter) is all access to the mountain's three - four if including Italy - areas. With the ski pass, you can ride all the lifts, gondolas, trains, etc., all up and down the mountain areas. If you are planning on mixing sightseeing with skiing/snowboarding, or sightseeing every possible point on the mountain, or skiing/snowboarding all day, this is your best option.
Also, for future reference, here is the panoramic map (in PDF) of the entire mountain: https://www.matterhornparadise.ch/pdf/panoramakarten/winter-17-18.pdf
Note, this applies to 2017/2018 winter.