Canon EF 50mm f/1.4 USM
This is a lens which has its own distinct strengths; it's ideal for users looking to buy a relatively small, lightweight prime, in order to gain image quality simply unavailable on a zoom for the same price. It's an excellent companion to full-frame DSLRs, and also doubles pretty well as a portrait lens on APS-C cameras.
Lightweight, sharp and versatile. This inexpensive prime lens is a great traveling companion for full-frame and APS-C DSLRs.
Shooting 'wide open'. The dreamy softness at F1.4 won't appeal to everyone, and corner sharpness isn't great at the widest apertures (not that it matters much).