Ad Injection - This plugin really is packed full of features, it supports pretty much any advert including major services like Google Adsense, ClickBank and Amazon Associates. There are a lot of options for deciding who sees the ads on your site, you can filter out ad serving based on IP addresses, you can also enable search engine only mode which will serve ads for visitors referred by search engines and block ad serving from everyone else, you can customise this setting even more by choosing exactly which search engine referrals or in fact any other referrals you want to block ad serving to and to those who aren't being served ads you can display alternate content. There is even an A/B split testing mode along with Ad rotation settings.
Advertising Manager - This plugin was previously known as Adsense Manager, but now includes support for a wide variety of the major advertising networks as opposed to just Google Adsense which means this plugin is even more useful than it was previously.
Advertising Manager offers multiple options for ad placements; you can insert ads via the sidebar widget, directly into posts or insert them into your template directly. Plus it comes with a handful of other great features, in my opinion this is one of the best Advertisement management plugins I have come across so far. Advertising Manager also made it to my list of best WordPress plugins.