In my opinion, Alonso and then Raikkonen, followed by Hamilton and lastly Vettel and Button. I have a feeling Hamilton may win a WDC driving a Mercedes, perhaps 2014 or 2015. If not in a few years, he may move back to McLaren if they are back near the front again, probably after Button has retired.
In my eyes, I feel Alonso deserves the 2006, 2007 championships, Raikkonen the 2005 and 2008 championships, Button the 2009 championship (driving for Honda ;)), Vettel the 2010 and 2011 (also now most likely 2013) championships, Hamilton the 2012 championship. I do feel Alonso deserves 3 titles, and with a bit of luck this could have already happened in 2008 (with a McLaren), 2010 or 2012 (in a Ferrari). Into the future, it’ll depend on how Ferrari improve their design team working with computers instead of track testing, and how they adapt to the new engine formula.
Alonso definitely deserves to be mentioned in the same breath as the best in the sport – same with Raikkonen and the other 3 drivers as outlined here. Their careers have all been exemplary. I feel Alonso and Raikkonen remind me a little of Clark and Ronnie Peterson. Personally, I feel Fangio, Clark and Senna deserve 6 championships, Schumacher 5, Prost 4, Moss, Stewart, Lauda and Gilles Villeneuve 3, Ascari, Brabham, Fittipaldi, Mansell, Hakkinen, Raikkonen, Alonso, Vettel 2, Rindt, Andretti/Peterson, Jones, Reutemann, Piquet, Montoya, Button and Hamilton 1 as of this year.
Part of me wished Alonso could deserve the 2013 championship, but momentum seems to be swinging towards Vettel, and he needs another non-race to be level with Alonso’s 2x non-races, but his car is still a lot better than the Ferrari, probably more with the 2012 tyres, which will give him the title when we head to the October circuits (Singapore, Korea, Japan, India, Abu Dhabi) which he always seems to win. I’m more sad at the fact that the tyre switch could lean the momentum towards Vettel. With RB always spending the most money every year, we need the momentum to swing away from them!