Not if the $800 chairs are substantially more comfortable. Keep in mind that the $800 chair will last several years, so the cost of giving a programmer such an expensive chair is miniscule relative to their salary. Joel Spolsky (a big fan of the Aeron) has written about this subject at length:

http://www.joelonsoftware.com/articles/FieldGuidetoDeveloper...

We spend a lot of time sitting. I want myself and the people who work for me to be comfortable. $800 isn't much to spend on something you use all day, every day.