depends on where the ads are displayed. I always make sure that text ads or image ads are placed so they fit into the aspect of the page.
You might find this interesting considering the source, especially this part: Personally I like throwing some image ads in the mix. Helps keep things fresh.
Based on my own experience I must say text ads are far more better than image ads. If you are looking for high CTR go for text ads IMO.
yes i think you should choose default settings. But personally i like image ads because it would be more attractive.
I also vote the image ads because I believe most people will see an image add they like and click in, rather than click on some advertising text. It all depends on how much space your website has and how you have it laid out. ~ Mike
Yes, this is also good. But I also believe that blending them to look as if they are "Meant to be" there on your site, can sometimes be a breach of the Google Adsense Terms Of Service. I really would not want to see anyone loosing their accounts.... ~ Mike
I believe that is only true if you are purposely trying to make the ads look like they aren't ads. I only make the colors match so it looks better and isn't as obvious it is an ad. Makes it less obtrusive. I have clearly laid out locations for advertisements. I also don't mess with the padding so they are spaced normally... they aren't extremely close to images or anything like that.
If you choose only image ads you'll have an empty place when there will be no ads related. Better choose both.