Film is a hard subject to tackle because everyone you talk to will have a different opinion and I'm no different. I can't recommend the perfect film for the View-Master camera, but I can give you some pros and cons of a few films that are out there if you are just getting started.

In my opinion there are three major factors that need to be considered when choosing film. These are Color Saturation, Grain, and longevity. I will try to list the pros and cons of some of my favorite films below.

Velvia now comes in three versions. Velvia 50 (Classic Velvia) was discontinued for a short while, but is back by popular demand.  This is THE best speed for the View-Master camera in my opinion.

Velvia 100 (RMS 8) and Velvia 100f (RMS 8) are the faster versions. Both have high saturation dense blacks. Grain is almost non existent. The major problem with all Velvia is that some skin tones don't look natural (anyone with a ruddy completion), (but Velvia 100F IS better for people shots in this regard, and slightly less saturation in the red range) and the dark blacks can cause harsh shadows on peoples faces. For landscapes (or anything where people are not the primary subject) this is an excellent choice. You can loose a little detail in shadows because of the enhanced blacks, but it does give a nice punch to your pictures. Many people think Velvia typically runs a little shower than rated, 100=80. I shoot it as rated however and am pleased with the results.  Since in sunny situations with a light colored subjects ISO 100 can still cause slight over exposure when your maxed out at f16 and 1/100 Velvia is a really good choice. If using ISO 100 I suggest getting some ND3 (Neutral Density .03) filters to cut the exposure by one stop when needed. I use some 37mm ND filters with an adapter ring, but you might can find some actual Series V ND3 filters.

Fuji's Provia 100F has the same great grain as Velvia 100f. It has an RMS value of 8. I have used this film a lot and like it quite a bit but miss the extra saturation I get with Velvia. This film has good color saturation, but leans toward the accurate side. I find that it works very well for people pictures and indoor flash pictures.

Fuji Provia 400X is a great film if you need the extra speed. It has an RMS value of 11, which is it's main drawback, but it's the finest grain available at that speed. For VM shooting indoors it can improve your depth of field by allowing you to use a smaller aperture.

Fuji Astia 100F has an amazing lack of grain (RMS 7). It's made to accurately reproduce skin tones and it does this very well. It has less saturation than Velvia or Provia however.

Kodak's Pro E100VS, E100S and E100SW are great for color saturation. VS is comparable to Velvia, but I find Kodak's film to have better skin tones while still giving great color saturation. Velvia has better grain though, so if I'm shooting landscapes that's what I go with. For the View-Master format the major drawback with this film is grain. Keep in mind that the View-Master format is around half the height and width of a normal 35mm film slide and in high magnification viewers like the model D, grain can become very apparent. The Kodak films RMS value is 11 for VS and 10 for the S and SW (lower is better) and in some shots this is not a big deal, but anything with a lot of sky in it will show grain. This film uses the common E-6 Process for quick turnaround when processing.

The new Kodak E100G and E100GX has great grain (RMS 8)
I have done some testing of it and I thought it's shadow detail was a little muddy. The highlights appear to wash out real easy as well. It's OK, but not great.

Kodak's Kodachrome is the king of longevity. It's estimated that in good storage that it is stable for 150 years. No one knows for sure because it's only been around for a little over sixty so it may last even longer. It has pretty good grain at slow speeds (RMS 10 for ISO-64) and good color saturation. It has a major drawback in that it is only processed in a very few places (K-14 Process) in the country and you typically will have to wait a couple of weeks to get your film back (all others on this page use the E-6 process). The labs are getting fewer and fewer, but I know Dwaynes Photo still does it.

I currently use Velvia 50 and 100 with shots that don't focus primarily on people. I will use 50 in all my classic cameras that top out and f16 and 1/100 until they discontinue it.

For shots that have people, i'm shooting Velvia 100f and Provia 100f. Velvia 100f does a pretty good job on most people shots without making people look like they have a sunburn, but you still get "burned" some times.

Related link: How film is exposed