Lefthandpalm dares go further and predicts that 2010 will be a scorcher, globally. This breaks the usual trend of hot years such as 1998 or 2005 being followed by cooler years, a pattern which suggests seasonal variation (early/late winters, long/short summers) has played a significant role. But even though 2009 was a very hot year (2) globally, I suspect that 2010 will be almost as hot, if not as hot. I say: top five for sure, almost certainly top three.
To forestall any accusations of weaselling, later on, I'll say now 'll be using the GISS data set.
1 - "A mild start to winter, and the end of el nino," press release by NIWA, 29th of April, 2010. Reproduced on stuff.co.nz. (http://www.scoop.co.nz/stories/SC1004/S00068.htm)
2 - "2009: 2nd warmest year on record: end of warmest decade," press release by NASA-GISS, 21st of January, 2010. (http://www.giss.nasa.gov/research/news/20100121/)