You can get into a discussion about this for hours, but my advice focuses on three main points:
1) Buy the best lenses that you can afford. Cheap lenses often result in low contrast, low color, soft photos.
2) Don't buy "crop sensor" lenses (like Canon EF-S and Nikon DX) unless you have a specific reason to do so . Some day, full size image sensors will get cheap enough to make that the manufacturers will probably end up putting them in most of their cameras. If you then buy a full sensor camera you'll end up owning a bunch of specialized lenses that won't work properly on full sensor cameras. Buy full frame lenses unless you have a specific reason not to.
3) For most people, good quality zoom lenses are perfect. Buy a "wide zoom" (17-35 mm), a "normal zoom" (28-135mm), and a "long zoom" (70-300mm). Most manufacturers make zooms somewhere close to these focal ranges. I shoot lenses with these ranges and almost never find myself needing any other focal lengths for general photography. If you have one good quality lens in each range, you're good to go.
For more information on this subject, there's no reason for me to repeat what has already been written in this good article from Outdoor Photographer.