I have a basic idea of film speeds now, but I've no clue what the difference is between the film, ha, if that makes any sense. I want to get decent quality shots, but when looking around at my local convenience stores I see what looks like just general film for the everyday point and shoot camera user. Is there anything I should look out for when purchasing color film? Right now I'm looking to buy a roll of ISO 400 color 35mm film, I plan on going to Chicago tomorrow to work on some street photography and get some people shots in as well, so I wanted the faster speed for the easier candid shots and whatnot (it'll probably be mid-late day, partly cloudy). I know it probably isn't TOO wise to try for more 'professional' expensive film when I'm still learning, but I want to get a feel for it at the same time and see what I can really do with my ol' Canon A-1. Any suggestions?