Well, in my humble opinion. I think Adsense is the best.
Google pays out well (or maybe with some delays).
They wouldn't want to "play" with their company's name (or would they)?

Besides, the control panel (where you view your earnings and stuff) is very user friendly. (actually this doesn't really matter that much, just my point)

Another point, they serve the most relevant ads. I think no other PPC companies serve ads more revelant than the ads Adsense provide.

My experince with google adsense:
If you fool around by clicking on your own ads (or asking someone else to click on them), prepare to lose your account. I lost my own account once, for not complying to the ToS. I told someone my earnings, and two days later I received the notification email that my account has been banned. Just to let you know, Google Adsense(the big brother) is always closely watching you and never attempt to try anything against the ToS.

Sorry if i crapped too much. To anyone out there who havent got a PPC account, Adsense is worth a try.

Right now, I think the best PPC program is Google's AdSense ads. Not only do you get paid good amounts, but the material, within the ad, is relative to the content on your page. For example, if your site is about music, the links will be to sites that deal with music.

Adsense is my best followed by searchfeed.

I have not tried Adbrite, but will be looking into it soon.