Tareq -- I think you'll get a lot of different answers from a lot of different people. I know it's tempting to want to try a lot of different films (I've been there myself) but it would probably be best to stick to one (or two) emulsions for now. Maybe one high speed and one low. I started with Tri-X (400), developed in D-76 because that is a classic, classic combination and I've had very good results with it. I now mostly use HP5+ (from Ilford, very similar to Tri-X) because it was more readily available (and cheaper) in Europe when I was living there. For 100 speed film I tried a bunch of different ones before settling on Fuji Acros 100. These are the two films I use 90% of the time -- I've been using them for a few years now (well, the Acros for less than a year) and I'm happy with what I have been getting. If you don't like grain you might try Kodak TMAX films or the Delta ones from Ilford.
In all honesty, I don't think it's necessary to have a bunch of different films for different subjects, especially if you are just beginning. Pick a film, shoot it -- all subjects, all lighting conditions -- and figure out what you like and don't like. Then you can try other films, once you know what you are looking for.