I've previously written about what lenses you should buy to build out your kit, and I only have one addition I'd make to that list today: the Canon 24-105mm f/4L (Amazon affiliate link). Although its low-light capabilities are lacking, it's super versatile, and with the built-in image stabilization, it can be more useful than the 24-70mm f/2.8 in some cases.
Recently browsing through The Wirecutter–a site I respect and trust for their in-depth reviews and emphasis on quality over junk–I was reminded of a comment I left three years ago. It was on a review titled, "The First Canon Lenses You Should Buy." Since that list remains mostly unchanged three years later, I thought it was a good idea to republish my comment here. Hopefully this finds people who aren't sure about what lenses to buy.
The following has been edited only slightly for context and clarity.
I was really surprised by the recommendations in this article. I'll preface my comment by saying I don't shoot photos, only video, but I shoot video exclusively on Canon DSLRs. I shoot with a 5D Mark III, 7D, 60D, and T2i. That said...
When people ask for lens recommendations, I always say: Don't throw away money on cheap or "passable" lenses. I would never tell someone to go buy a 5D Mark III and throw a 50mm f/1.8 on there.
Lenses can move from camera to camera. If you take care of a lens it can last a lifetime. A camera body will be replaced in what, 5 years? 3 years? For most purposes, you're better off starting with a cheaper body–a used T2i is (still!) a great buy–and then get the 50mm f/1.4. The 50mm will be a great lens even if you move up to a 5D in a few years.
On a crop sensor body, you also may be better off (depending on your needs) to get a 28mm or 30mm from Canon or Sigma. These are also generally in the $300-400 range and will give you an image closer to a "true" 50mm on a crop body.
The 70-200 seems like overkill for this type of list. You should at least be comfortable with the camera before dropping $1000 on a lens. For that price range though, pick up an older model 70-200 f/2.8L or the 135 2.0L (a beauty of a lens that's often overlooked). The point being, put the money into a lens you're sure you'll use (and love) for years. Not something just so you can have a full kit.
The 100mm macro is a very nice lens, but unless you specifically need the macro capabilities, an alternative there would be the 85mm f/1.8. Another great lens that is sometimes under the radar.
Whatever lens you go with, the advice I try to ram into everyone's head is to look at your lenses as an investment. Camera bodies will be replaced. Spend the extra money (or save until you can afford it) for a lens that will last you a long time.
I will say I like the recommendation of using the 50mm f/1.8 as a relatively cheap way to find out what focal length you like. Good call.