There have been many reports which indicate that, for a variety of reasons, linen is more 'environmentally friendly' than cotton. (e.g. "The Role and Business Case for Existing and Emerging Fibres in Sustainable Clothing", Defra 2010).
I admit that most of the time I simply wear whatever's cheapest in Asda, Primark or charity shops but I do like the crisp feel of a linen shirt. (They're also great to pack when travelling, as they simply retain their naturally rather crumpled look, rather than acquiring lots of unsightly creases).
As Togo indicates, linen won't shrink when washed in accordance with the instructions on the label.