Well wondering which types of attracts more than others? According to Google the wide ads are more attractive than the slender ones.
It says 728×90 will always perform better than a 160×600 (Width x Height). It is related the way humans read, as we usually read content in a single, it is expected that the ads displaying information in a single line or Horizontal way is more attractive to users.Its good for users hence good for publishers. In my experience I have seen the ads placed right in middle of your site just above the content performs very well.
But if you start placing ads in the middle of your page many users may get irritated or your site will look ads oriented rather than content oriented. Its upto you to bring in a balance.
The link ads can be added anywhere and here also the wider ads in a single line saves more space and brings good exposure.
Best performings ads in order of performance
1. 336 x 280 or 300 x 250
2. 728 x 90
3. 468 x 60
4. 160 x 600
728 x 15
468 x 15
.. to be contd