It's The Brick
This is the nicest standard zoom lens you'll find. It's sharp, high-contrast, and low aberration at nearly all zoom levels and apertures. If you're going to step your toes into Canon's L line, this is the place to start. Giving you five standard focal lengths (24, 28, 35, 50, and 70 mm) this lens is an ideal high-quality everyday lens. Further, the quiet USM autofocuses nearly instantly, and the full-time manual focus ring rotates like butter.If I had to pick one problem with this, it would be the weight. At about 2.5lbs, it's surprisingly heavy, especially when you've been wielding it for several hours. Also, it's immense size grabs the attention of strangers, which depending on what you're doing, could be problematic.But in the end, when what I'm doing demands high quality and versatility, this is the lens I rely on. It is the standard-zoom staple of my travel pack, and if limited to only what's attached to the camera, this is the lens that comes.