Theres lots of good tobaccos out there. First you have to decide if you want to smoke Aromatics or Non-Aromatics (English). Then you have to go to a smoke shop or an online vendor and either ask or read about some tobaccos. Or you can start here
http://www.tobaccoreviews.com/ you can read reviews on 1000's of tobaccos.
There are so many types of pipe tobacco its hard to give good advice on what to smoke, its kind of a trial and error thing to find what you like. Remember, Aromatic tobacco is kinda like flavored cigars, you taste the candy flavoring and not much tobacco. I only smoke Non-Aromatic and English tobacco, you taste just tobacco.
After alot of researching the subject Ive found this place,
http://www.pipesandcigars.com/pipetobacco.html Has the best selection, customer service and prices. They have bulk and sampler deals all the time, check it out.
The last thing you could do is to go to the drugstore and buy some of their tobacco. Its like smoking white owl cigars but its cheap and easy.
(correction: Prince Albert is a decent DS tobacco in a pinch)