Should I buy MacBook Air?

Today I bought 4th generation Ipad. When looking for it I saw MacBook Air and I think it's awesome. Should I buy it or will it be unnecessary expenditure? I want to buy the model with 11.6", 2gb ram, i5, 1.60ghz, 64 gb, 256 mb graphics card. I just want to use mac so I want buy this one. What do you think?
I'd appreciate any help I can get.