If you've got a Canon EOS 7D, you've either got the body only version or one of the 3 lens kits with either the EF-S 15-85mm lens, the EF-S 18-135mm lens or the EF 28-135mm lens. They are all decent options but you have to be honest that kit lenses are just not on the same par as most of the lenses you have to purchase separately. I will make one exception with that being the 24-105mm L lens that is sold with the Canon 5D Mark II but let's digress. Our pick for the 5 lenses you must have is balanced between quality and budget. Look to the end of you want to know what to get regardless of price.
Prime Factor - Canon EF 50mm f/1.4 USM Lens There is no doubt that every photographer worth his salt will have at least one prime lens and the Canon EF 50mm f/1.4 USM lens is definitely one which you must have. With an APS-C sensor where the 35mm equivalent would set it to 80mm, this lens is extremely useful for portraiture photography as well as situations where a fast lens would be required such as indoor, low-light photography.
The Standard Zoom - Canon EF-S 17-55mm f/2.8 IS USM
While at first look, the price tag may be high for this non-L lens but the quality of the Canon EF-S 17-55mm f/2.8 IS USM is definitely as good as any L lens that you can buy. Considering the focal length when used with the Canon 7D and you will be getting the equivalent of roughly 27-88mm. This is pretty much (and a bit more of) the focal length of using the 24-70mm f/2.8 L with a full frame body. The barrel of the lens may not have the L lens finish but for the price difference (from say a 16-35mm f/2.8) and the quality the lens can deliver, we think it's a good buy.
The Telephoto Zoom - Canon EF 70-200mm f/2.8L IS II USM Lens
The Canon EF 70-200mm f/2.8L IS II USM lens may be the priciest lens from this selection but it is definitely worth every penny. Using the latest image stabilization technology from Canon, this lens takes on the mantle of most popular telephoto zoom from its predecessor with full aplomb. Great for a lot of different shooting scenarios and even with the crop factor, it still allows you to take great portrait shots. With its large aperture, you can afford to lose 2 stops of light for the extra reach when used with a 1.4x/2x teleconverter especially when the IS of the lens is supposed to give you a 4-stop advantage.
The Wide-angle Zoom - Canon EF-S 10-22mm f/3.5-4.5 USM Lens
With a full frame sensor, you could use the 16-35mm f/2.8 to capture wide-angle shots but with a crop sensor camera, getting wide-angle shots is only possible from a much more limited range of lenses. The Canon EF-S 10-22mm f/3.5-4.5 USM lens is really the only Canon zoom lens up to the job. While the aperture may not be as very wide, it does deliver solid performance that makes it a necessary inclusion in your camera bag should the need for wide-angle shooting arise.
The Super Telephoto Zoom - Canon EF 100-400mm f/4.5-5.6 L IS USM
While a ultra telephoto prime can give you more in ways of image quality as well as maximum aperture, shooting wildlife may call for a bit of flexibility with a zoom lens. This is especially true if you can't move from your position to recompose at a further or nearer position. The Canon EF 100-400mm f/4.5-5.6 L IS USM combines image quality and flexibility neatly into one package to satisfy your creative freedom.
Alternative to the Super Telephoto: The Macro Prime - Canon EF 100mm f/2.8L Macro IS USM
We understand that the final choice of the list may not appeal to everyone. After all, the 320mm equivalent reach of the 70-200mm is not too shabby for most general situations. The Canon EF 100mm f/2.8L Macro IS USM is a top notch macro lens which delivers excellent sharpness. An L lens which delivers better image quality than its non-L counterpart as well as image stabilization for handheld shooting. This lens allows you to shoot within the studio on a tripod or out in the field handheld.If money was no object? Try the "Best 7" Instead
Well, while the above lenses are my top choices to have with the Canon EOS 7D, I would go with the following lenses if I didn't have to worry about my bank balances:
The Canon EF 100-400mm f/4.5-5.6 L IS USM and Canon EF 100mm f/2.8L Macro IS USM remain great choices for Super Telephoto and Macro shooting respectively and so would definitely earn a place in my must have collection.
Canon EF 50mm f/1.2L USM instead of the Canon EF 50mm f/1.4 USM lens because the image quality of the L lens is much better while the larger aperture allows you to go just that little be faster.
Canon EF 16-35mm f/2.8 L II USM and Canon EF 24-70mm f/2.8 L USM instead of Canon EF-S 17-55mm f/2.8 IS USM because no matter how good the 17-55mm, there is an allure to being the proud owner of the "Big 3 Zoom" from Canon. You may need to use 2 lens for segments of the standard range but the images will tell if you use them right.
Canon EF 70-200mm f/2.8L IS II USM instead of? instead of what? Sorry, this is still the best! Non-negotiable and definitely what you want to see.
Canon EF-S 10-22mm f/3.5-4.5 USM is the same story. As I've said, to get these wide-angle focal lengths from a cropped sensor DSLR, there really are no alternate choices unless you go to third-party brands. Mind you, if you ever move on to shooting full-frame, this lens will become redundant just like the Canon EF-S 17-55mm f/2.8 IS USM.