I have a website where I review useful and/or fun electronic gadgets (RC helicopters, LED flashlights, mp3 players, the like).
I've run it for some time with a barebones layout with no ads because I was just getting started writing the reviews.
Now I'm moving to a proper layout, which has a space I have reserved for contextual advertising. I don't want anything invasive, just some ads that might be of interest to people reading my site while hopefully making me a buck or three.
The problem is that I don't know the first thing about advertising. I've tried Googling a bit, but I've found many pages with different opinions about what's best. What I managed to learn is that a lot of people are using Google AdSense, but that there are other services such as AdBrite and Yahoo that offer basically the same thing.
What do you think is the best one and why? Also, is there anything important I should know?

Thanks.