Desk lamps are wonderful work horses. There are so many different styles, they don't have to be the archetypal desk lamp - they can be rustic, minimal, cosy, pretty ... the list goes on. Match your personality when choosing your desk light. There are a few other considerations as well, such as desk space and foot print size, whether flexibility is important to you (do you want to swing it around, move it up and down, etc or are you fine with a static table lamp that doesn't move?) Another consideration is how you switch it on and off (or dim it) - a thumbswitch is really useful, meaning you don't have to search down the cord for the switch or use (yet another) wall switch. 

Top Tip: An ideal location for your desk light is below eye level and above your surface. This avoids fatigue by cutting down glare and minimising shadows.