Dave
Recognisng all the different flies takes time , its not something that happens overnight , log on to the following site and scroll through the different sections and you'll get an idea on all the flies and their names.
I buy a lot of flies on this site and can reccomend them
http://www.fliesonline.co.uk/Once you have fished for a while you will build up your collection of favorite flies, generally ones you have caught fish on and have confidence in. You will pobally want a box of lures , wets, dries, nymphys and buzzers.
Now once you have fished for a few seasosns you may wish to consolidate your favourite into one box , don't do as I do and have 15 boxes in case that pattern i bought in 1982 turns out to be killer one day
Jim