Well it depends what you're shooting for. There are negatives and there are slides. Then there is black and white and color for both. The biggest difference is the way they are developed.(posted 8635 days ago)Color negatives - the most common consumer form of film. Most of it is processed C-41, which is the 1 hour stuff. Great for snapshots of Aunt Edna.
Color slides - Same as color print film but no prints. Usually they are put into a projector and you get a slide show. Aunt Edna and Uncle Barney's summer vacations of '58 and '59. Most of these are processed E-6 except Kodachrome, which is processed K-14. Some photo development places can develop E-6 slides for you in a short amount of time. For the Kodachromes, they need to go to one or two labs in the country that can process Kodachromes. Mind you, you can get prints from slides. Usually done in two formats: Cibachrome and internegative. Cibachrome is where they use the slide to expose color paper. Internegative is where they take a full scale picture of your slide.
Black and white negatives - two camps here. Traditional B&W which needs special development. You can take it to some photo finishers to have them develop it for you but be prepared to shell out some bucks. (I paid $20 to have a roll of traditional B&W developed and printed on 4x6 paper - that was when I decided that I would learn more about developing my own) Most people on this list use traditional B&W film and develop their own. The second camp is chromogenic film. B&W film that is processed like a one hour color print (C-41). Not any B&W film can do this. Three films come to mind: Ilford's XP-2, Kodak's T400CN and Kodak's Black and White+. These three films are great if you want to break into B&W without doing all of the lab work yourself (that will come later when you get hooked).
Black and white slides - Only one player in town: Agfa SCALA 200.