This article summarizes the probably best tablet magazines so far. I might have missed one, then please provide the link via comment to this article.
If you search for cool iPad magazines you might buy these ones here. They all are very cool magazines and worth the price they cost. The pictures shown here are just screens of the current issue and might be outdated directly after publishing this post. Please make your own opinion and share it on iTunes :).
NOTICE/CREDITS: image credit is to the vendors of the linked magazines. Credit link is available on linked iTunes App description. I use the pictures to give users the chance to buy/download these magazines and help making the magazines more popular.