A couple of things to consider when buying a light fixture:
Why am I lighting the space? How much light to I need?
A work space: you need the room to be well-lit in general.
A dining room: opt for mood lighting vs. task lighting.
A living room: your ceiling fixture(s) just adds to the general ambiance, while lamps and picutre lights illuminate certain zones in the room.
The kitchen: definitely go for concentrated task lighting.
Your bedroom: a pair of wall sconces might lend a flattering glow but enough provide light to read by.
The bath: overall lighting for the ceiling fixture, and concentrated light near the vanity.
Here are a couple of my faves for the office from my top online sources for style. Of course, I want to keep it as cheap as possible, but I am seeking a modern fixture to add punctuation to the space. Tell me what you think.
At $129, the highest price, is West Elm's faceted glass pendant. It lends a sort of rustic and refined element, but remains contemporary with the clear bare bulb. It only accomodates a 60 watt bulb and is about 14" in diameter.

Ikea's Leran pendant boasts nautural elements and a very modern shape. At 24" wide, it certainly would provide a great sense of scale to the office. It is $90 and can take up to 150 watts.

My most fave, and the least expensive option, is cb2's Eden Pendant. It is clean and simple, totally mod, and only $50. At about 20" in diameter, with a 100 watt capabilty, I think it would be the perfect size and provide ample illumination.

Any thougts on what look I should save up for? Here are a couple photos of my office so you can make a sound decision.

