Leaving aside our hopes that 7-time world champion Michael Schumacher will actually become a title contender in 2011, this will be the first time in more than 4 decades that an F1 grid will include no less than 5 world champions.
Schumacher (7 titles), Fernando Alonso (2 titles), Lewis Hamilton, Jenson Button and Sebastian Vettel (one F1 crown each) will all try to bag another one next year. What's even more interesting is that the 2011 lineup could have included 7 world champions, which would have been a world record in F1, had Kimi Raikkonen and Jacque Villeneuve secured a return in the series.
Raikkonen has remained committed to rally racing for 2011, but left the door open for a potential return to the Great Circus in 2012 (probably with Red Bull Racing). As for Villeneuve, the Canadian driver tried to secure an F1 entry as a team owner/driver with Durango, but those plans failed.
The last time 5 world champions took the track in Formula One at the same time was back in 1970, when Jack Brabham, John Surtees, Denny Hulme, Graham Hill and Jackie Stewart were all part of the F1 entry list. None of them managed to secure the title that season, as the honors went to posthumous world champion Jochen Rindt, who was killed in an accident at Monza.