Right next to me right now, I have a chinese-made flourscent desk lamp that uses a 27 watt bulb. It's a Sunpentown "EASY EYE" desk lamp. This lamp however is pretty hard to find right now but I think a similar,if not identical lamp would be the Verilux "Happy Eyes" desk lamp.
It lights up part of my "L" shaped desk right now but I can tilt the head back a little more (It has a gooseneck) if I want to light the other half of my desk.
Easy Eye Lamp.
Note: mine is and older model and has the on/off switch on the base. This one has a dimmer switch on the neck
On the other hand, you could always hang a 4 foot shoplight with 2 of your favorite brand of full-spectrum tubes above your desk and have a lot of light to work with.
Hint; If you're right handed and use a desklamp, put the lamp on the left side of your desk. That way, you hand dosen't cast a shadow over the page as your write