Adsense has been the best option for almost all my sites.
The trick with Adsense is you need to optimize it for your site. The ads need to be placed in spots that draw attention and in turn click-throughs. Here is a chart of the hotspots:
https://www.google.com/support/adsen...ium=link#17954
You also want to have the ads match with your design. You can have it blend in or you can have it really stand out by making it a completely different color. My suggestion there is to test a few different color schemes and see what the best one is in terms of CTR.
Finally, you want to watch it and see what ads are showing. You can block out irrelevant sites which can cause a lower CTR. Also remember that a lower CTR and low conversion rate can cause your "score" to drop and you will not receive as much per click.