Ilford FP4+
FP4+ is the first black and white film that I became familiar with. At a recommended ISO of 125, FP4+ is classified as a medium speed black and white film, but for me, I would consider it a slow speed film. I don't think most modern films dip that far below ISO 100 these days. The modern films like Tmax 100 can achieve an extraordinarily fine grain while keeping medium speeds, so it makes slower films less practical. The exceptions would be Agfapan 25, Ilford Pan F, and perhaps Kodak's Technical Pan, which is more of a specialty film. These concerns are largely for 35mm. When using a film like FP4+ on a 6x7 or 6x9cm camera, grain is a non-issue. Enlargements to fit your wall would have acceptable quality.
FP4+ provides a beautiful tonal range, extremely fine grain, and it seems very tolerant of exposure errors. I have never had images that could not be salvaged unless I failed spectacularly. The downside to FP4+ is that it is too slow for shooting in very low light and it lacks some of the punch that films like HP5+ and Tri-X thrive on.
It is a low contrast film, and at its worst it can be fairly flat. It is an excellent film for portraiture, as the lower contrast tends to deemphasize skin blemishes. The following image of two pigeons was taken on the first roll of FP4+ that I ever shot, and I think that it is quite representative of what to expect with the film.
This image demonstrates the lack of grain and the delicate mid-tones that characterize FP4+. The slight fuzziness in this image (I see some around the pigeons' heads) is a result of JPEG compression artifacts, not film gain. The film gives a long range of grays that lend a sense of naturalness to the photographs. Where a film like Tri-X or HP5+ may grab your attention more viscerally because of higher contrast and more grain, FP4+ gives a more artistic or painterly quality. In other words, if you are going to shoot a photo essay on street children, grab some Tri-X; if you are interested in making flattering portraits or solemn images of park benches covered in wet snow, grab your FP4+.