MGSO (by the why on earth is it officially called "Morrowind Overhaul - Sounds and Graphics" when written out, but MGSO for short? I've also seen MSGO used, but on the http://www.ornitocopter.net/morrowind-overhaul/ and http://www.ornitocopter.net/mo_wiki/index.php?title=Main_Page they call it MGSO) is certainly alright but not very up to date, and they did not get permission to use some of the best and most popular mods in it. So you may want to take a look at http://download.fliggerty.com/download-127-874, which is my personal favorite, as well as http://www.nexusmods.com/morrowind/mods/43110/? Head Pack for the Khajiits. More recently, http://www.nexusmods.com/morrowind/mods/searchresults/?src_order=1&src_sort=0&src_view=1&src_tab=1&src_language=0&src_auth=mackom&src_showadvlt=1&page=1&pUp=1 have become quite popular. I personally can't stand them because I find them lifeless and somewhat creepy, but many people seem to like them, so it would be unfair not to mention them, and they were certainly made with a lot of skill and effort.
If you are going to use MGSO (you can still install the other heads on top of it if you like), you will also want to improve the bodies in addition to the faces. Of course, there is still http://www.nexusmods.com/morrowind/mods/42395/? (as well as http://mw.modhistory.com/download-21-14097 to go with it), but now there are also http://www.nexusmods.com/morrowind/mods/43138/?, although I haven't tried them myself, yet (the author, http://www.nexusmods.com/morrowind/mods/searchresults/?src_order=1&src_sort=0&src_view=1&src_tab=1&src_language=0&src_auth=moranar&src_showadvlt=1&page=1&pUp=1, has also made a number of armor mods for better bodies you should take a look at).
That should get you startet for the moment. For everything beyond that, you should probably go to the Morrowind section and create a new topic there.