The Nikon 50mm f/1.4G does everything right, so is our winner. It's a good weight and feels well balanced on the camera. Build quality is reassuringly rugged, and the ring-type ultrasonic autofocus system works a treat on any Nikon body.
The lens gives a dreamy look to portraits at its maximum aperture, and is super sharp at mid-range and small aperture settings across the whole image. The diaphragm is based on nine curved blades and helps give beautiful bokeh that's soft and sumptuous.
Plus, considering it costs less than the bulkier and heavier Sigma equivalent, it's a bargain.
Modernity isn't everything, of course, and proving that classics still have a lot to offer the digital photographer, Nikon's 50mm f/1.8D delivers spectacularly sharp images with bags of contrast and is an absolute steal at £100/$125.
However, it won't autofocus on bodies such as the D3100 and D5100, which lack a screw drive for camera-based autofocus actuation. Therefore, the newer Nikon 50mm f/1.8G is the next best thing if you're on a tight budget.
The Sigma 28mm works best as a wide-angle lens on full-frame cameras, but is a bit on the large and heavy side for a 'standard' prime on APS-C format bodies. The Sigma 30mm is a better option for DX shooters but isn't without its flaws - the most noticeable is a lack of sharpness at the edges and corners of the frame.
The Sigma 50mm f/2.8 and Tokina 35mm f/2.8 macro lenses offer full life-size magnification at their closest focus distances but, ultimately, the smaller maximum aperture makes them a bit of a compromise for general shooting.