Oh boy, i could not eliminate this list to a top 10, and hey, why? :)
As a start here my personal favorite cover designs 2011 so far.
(if you have another great cover design don't hesitate and please let me know!)

1. Magnes from Poland
2. Epoca from Brazil
3. Internazionale from Italy
4. Shoes-Up from France
5. Domenica from Italy
6. Fast Company from the USA
7. ESPN from the USA
8. u+me from the USA
9. Vogue Gioiello from Italy
10. Esquire from Russia
11. Metropoli from Spain
12. Epoca from Brazil
13. New York Times Magazine from the US
14. Time Out from the Netherlands
15. Playboy from the Netherlands
16. New York Magazine from the US
17. New York Times Magazine from the US
18. Suddeutsche Zeitung Magazin from Germany
19. Billboard from the US
20. Wired from the UK
21. Zeit Magazin from Germany
22. Internazionale from Italy
23. Playboy from Slovenia
24. The New Yorker from the US
25. Suddeutsche Zeitung Magazin from Germany
26. Bloomberg Businessweek from the US
27. San Francisco Weekly from the US
28. The Sunday Times Magazine from the UK
29. The Village Voice from the US
30. Bloomberg Businessweek from the US
31. Zeit magazin from Germany
32. Wired from the UK
33. UP from Portugal
34. Men's Health from the UK
35. GQ from the US
36. Esquire from Spain
37. Love from the UK
38. Vice various editions
39. Harpers Bazaar from the US
40. Bloomberg Businessweek from the US
41. Domenica from Italy
42. Creative Review from the UK
43. Southwest Airlines Spirit from the US
44. Financial Times from the UK
45. New York Magazine from the US
46. V Magazine
47. San Antonio Current from the US
48. New York Magazine from the US