The bigger ad units are better than smaller ad units as we are able to see it recently. And the best performing units are 336*280, 160*600. Now Google AdSense has added another one unit which will help to increase the income from AdSense. The unit is (300*600).
For obtaining an AdSense code for newer unit ie 300*600 unit, you need to login to your Google AdSense account and need to create ad unit for 300X600 ad size (large Skyscrapper). More of the text ads will be visible than visual ads as it is a newer unit. Different size of ads may run on this newer ad unit. Select and customize the design / color according to your website color combination. Also you can monitor the performance of new ad unit by creating a custom channel and comparing it with other performing ad units.
The surety is that this new ad unit will perform better than older ad units. It can be placed with your content page. You just need to increase size of your context box. Page layout may also be considered in mind as the ad should not be placed below the post of the title.
Since you already know, Google AdSense allows you to place just 3 ad units at one page, So if you are already having 3 ad units, you can replace one with this new ad unit, and update the default size for space adjustment.
Since many people are in doubt that big ads will fetch high CTR, so we are eager to look forward for your views.
If you are using this New Ad Unit, please share your views with all, as Google AdSense is bread and butter of many bloggers.