How should one answer this question about 年?
Just as you said

春节快乐！(chun jie kuai le, Happy Chinese New Year!) 今年是什么年？

you could answer 龙年.That's OK!
But 龙年 is not often used in Chinese culture nowadays.Even if in the ancient time,we use 壬辰年 to indicate the year,because there are 5个龙年 in every 60 years.However,there are also 1个壬辰年 every 60 years.So we use the 年号(emperor's symbol)to indicate the year,for example,乾隆50年（乾隆is the 年号 of one emperor of Qing dynasty）is 1785年，乙巳年 and 蛇年。 So it's safe to  answer your question like this:

someone: 春节快乐！(chun jie kuai le, Happy Chinese New Year!) 今年是什么年？
you:2012年，the doom year!
someone:haha，I know it's 2012 now, I want to know the lunar year!
you:Oh,sorry,it's 龙年！