Best 120 roll film
The medium format film market is surprisingly healthy, and the 120 roll film format is relatively inexpensive. It's versatile too, as some cameras use it for 6cm x 6cm square images, narrower 6cm x 4.5cm negatives or wider 6cm x 7cm or even 6cm x 9cm shots. Again, we've organized these films into color negative, black and white and color transparency films.
Medium format color negative film
This is the same Extar 100 film available in 35mm format, but this time on 120 roll film. Its combination of fine grain (T-Grain), high saturation and sharpness should make it good for all kinds of commercial work, and an alternative to transparency film for landscapes, scenic shoots and travel.
Kodak Portra 160 is a good choice for medium format portrait photographers, being optimised for smooth and natural-looking skintones. If ISO 160 is too slow, there are ISO 400 and ISO 800 versions too, though as ever with faster films, grain becomes an issue much sooner than it does with digital sensors.
You can get Lomography's distinctive yellow/orange/red colour shifts in a medium format version of its Redscale XR 50200 film. This could be ideal if you're going for a strong retro vibe and you're experimenting with an old medium format TLR, for example, or one of Lomography's own cameras.
Medium format black and white film
Ilford FP4 Plus is an evolution of a film that's been a favourite among scenic photographers for decades. It's an all-rounder, offering reasonable speed, good contrast and definition and pretty fine grain – though its characteristics will depend on which of many available developers you use with it.
The effect isn't quite the same as Kodak's long-gone HIE infra-red film, but Ilford SFX200 does have extended red sensitivity and, when used with a deep red filter, can produce attractive infra-red images. It's easier to load and handle than Kodak's film, too, needing no special handling precautions. It's worth noting that although this film is still available at some retailers, it has now been discontinued by Ilford so it won't be around forever.
Medium format transparency film
At 50 ISO you're going to want to use a tripod to shoot with Velvia 50. Although more commonly known as 35mm slide film, it's also available in 120mm medium format film as packs of five. The 35mm version is rather expensive but the medium format version doesn't seem like bad value at all.