I like Yahoo & Adcenter... it has nice conversion rates HIgh quality Traffic also u may try adflip from iwebtool which i havent tried yet and they give some bonus to start with also if u want my referal link to join then u may pm me..
If you can't use AdSense or YPN I always recommend AdBrite. They pay reasonably well (usually around 10 cents per click plus CPM earnings) and aren't as strict about what their publishers' sites look like. I find their inline ads are working particularly well for me - read my experience.
I've just started testing out Adengage. They have some interesting formatting options for the ads you display. You can have it show like a regular list of ads, like Adsense, or you can have it so that mini-thumbnail images appear with the ads. If you know a little CSS then you can really customize the look of the ads.
That may be so but AdBrite isn't contextual - it displays the same type of ads (and payment per click) regardless of the site content.
I think Adsense is the best but it's quiet hard to apply adsense account so far, I've heard about adchoises but never try this before.
There isn't any best Pay Per Click Advertising program, because the best program is that which generates maximum ROI, and every advertising program generates different ROI for same product and same campaign, some work pretty well with some offer while others not. Never stick to any one Pay Per Click advertising network.
I like adsense because of the keyword tool. Its good to do a combination of advertising for your website. Backlinking, hypertext, and the like. I also recommend paying for advertising through forums and directories also. Digital Point is one of the most well respected forums and sites on the net with a wealth of information. Paying to advertise on a site like this may have better benefits than adsense and the like. Think of it as advertising and restaurant or a store or the like. You want people to come to your store, so with that being said, advertise on high Pr and well respected sites.
Findology has PPC traffic starting at $0.03 cents US. They are currently offering $25 credit for $100 initial deposit. Promo code is PPC2012.