I use a number of lenses. Some I own, and some I rent on a regular basis. My two primary lenses include a Sigma 24-70mm f2.8 that serves as my “wide” lens. This is an older lens (and it’s starting to really show its age) but it’s served me well for a long time. This lens is part of Sigma’s professional series (they call it EX for Excellence) and it’s kind of big and heavy, but it’s pretty fast and really does the job when I’ve needed it to.
My most used lens in my personal collection is the Sigma 70-200mm f2.8 HSM and it is my workhorse. This lens almost never leaves my A900 body. This is another one of Sigma’s EX series of lenses and I’ve really given it a workout.
For my biggest jobs I’m a big fan of renting. I’ve used a lot of rental lenses and they have all been pretty incredible. My favorite lenses are the Sony Zeiss 85mm f1.4 (I use it on almost all of my portrait jobs) and the Sony Zeiss 135mm f1.8 (just a phenomenal lens). I’ve also used (rented or owned) the Sony 50mm f1.4 for a quick fast walk around lens, the Sony Zeiss 16-35mm (the finest wide zoom I’ve ever used), the Sony 20mm f2.8 (a pretty good fast wide prime lens), the Sony Zeiss 24-70mm f2.8 (an incredible middle range lens), the Sony 70-400mm f4-5.6G (an incredibly sharp lens with a ton of range), the Sony 70-300mm F4-5.6G (another really sharp lens I use for street photography), and the Sony 300mm f2.8G (the best long lens Sony makes) with the Sony 1.4x multiplier.
Lenses are a very personal choice and I’ve found that having the range from 24mm to 200mm covered seems to get most jobs done. I’m also a serious proponent of buying lenses that are designed for full-frame sensors. By buying full-frame lenses you are ready to go no matter what size sensor you have on your camera.