The basics of a core set of primes consist of a moderate wide-angle, a standard and a moderate telephoto, as well as a dedicated macro lens. Sports and nature shooters would add telephotos to this list, but a 500mm ƒ/4 isn't the sort of lens every pro would use on a regular basis, and it's tough to justify $10,000 for a lens that doesn't get a lot of regular use.
A good macro lens should be in every pro's arsenal. Designed for 1:1 magnification, these lenses are highly corrected for close-up work, they're sharp across their field of view, and they can be used for more than macro. A macro can be a good mid-telephoto, but a good mid-telephoto isn't necessarily going to be a good macro lens. Ideally, you want your macro lens to give you a comfortable working distance when shooting 1:1, and you want a fast lens to give you depth-of-field control and the ability to use fast shutter speeds
Wide-AngleA low-distortion wide-angle lens is a mainstay for street photography, photo-journalism and motion capture. If you're shooting with a full-frame DSLR, we're talking about the 24mm range; 20mm and wider fall into the ultrawide category, and these lenses will show significant distortion. As Cartier-Bresson is rumored to have said, very wide angles are like garlic; a little bit can enhance the meal, but a lot of it stinks.
Excellent options include 24mm ƒ/1.4 or ƒ/1.8 models. The fastest wide-angle zooms will be ƒ/2.8 at maximum aperture, and most of them are far from their sharpest at ƒ/2.8. A 24mm ƒ/1.4 prime, on the other hand, will be sharp at maximum aperture, and closed down three stops (for most lenses, this gets to the lens' sweet spot), it's razor-sharp. By the way, closed down three stops from ƒ/1.4 is ƒ/2.8.
For APS-C DSLR users, 24mm won't feel all that wide. A 20mm model will feel like a 30mm lens, which still isn't all that wide. You could go with something in the 15mm range, but those lenses are typically fisheye models that will show significant distortion, even on APS-C-sensor cameras. The Zeiss CP.2 18mm lens is oriented to motion capture, but still shooters with APS-C DSLRs who need minimal distortion in a lens in this focal length will find it useful. There's also a 15mm Zeiss CP.2.
StandardTechnically speaking, a standard focal length is determined by the diagonal of the image sensor. On a full-frame DSLR, that measurement is about 43mm, which you'll notice is smack in the middle between 35mm and 50mm. On an APS-C DSLR, the diagonal is about 30mm. Full-frame shooters tend to be split between having a preference for 35mm or 50mm as their normal lens. Do you like slightly wide or slightly telephoto? You have a lot of options for excellent 35mm ƒ/1.4 lenses. If you prefer the slightly more telephoto 50mm perspective, you can get 50mm ƒ/1.8 lenses for incredibly low prices; 50mm ƒ/1.4 models cost a bit more, but usually still below $500. There are also a few 50mm ƒ/1.2 options that give you some incredible low-light opportunities.
For APS-C DSLRs, the 35mm ƒ/1.4 options are popular choices as they have a similar look as a 50mm on a full frame. You could also choose a 28mm for a slightly wider look or a 24mm to get you close to a 35mm perspective.