Google Adwords.

Do you plan on voting in your own poll?

Adwords for sure then overture

I don't think this is much of a competition

I have voted "Google Adwords".
At present Google "The King Of Website Promotion & Internet Marketing" World.

I;m not using any of them at present, but I use adsense on my sites. Am pleased with it, so I think Adwords is also a good thing.

Nielsen/NetRatings, released recent market share data:

Google: 47.7%
Yahoo: 21.8%
MSN: 11.3%
AOL: 7.2%
Ask Jeeves: 6%
All the other SE's combined have approximately a 1.5% market share.

But, don't take that into consideration alone. Place tracking code on your URL's and webpages, and track. Test, Analyze the data. You might find that enhance interactive is the best converting SE, and not Google. You might get the best ROI on MIVA. Who really knows? It's different in each industry. BigResearch just conducted a study and found that in the Apparel industry the best converting SE's are in this order:
1. Yahoo!
2. AOL
3. MSN
4. Google
5. Ask Jeeves

So, if you are just interested in traffic volume, then Google is the answer. But, if you want to know which converts the best, then test and analyze for your individual results.

Hope this helps:-)

MSN has always produced the best audience for me. Surfers arriving from MSN stay the longest and visit the most number of pages in a session. But they just are simply not capable of delivering anywhere near the amount of visitors as Google is. And their PPC campaigns are way more expensive per click too! Unfortunately, even with Google's "lesser-quality visitors" as far as my specific traffic is concerned, it just doesn't balance out, and I have to stick to mostly organic with a little dash of AdWords thrown in.

I like Adwords i also like Overture i voted overture

Offcourse the best PPC service provider is Google without a doubt, the conversions are awesome but its a bit expensive.