Was looking for a reasonably priced office chair and found this here.  Love the fact that it has a head rest and didn't cost $500 or more.  Overall, the chair is quite comfortable, but the mesh material gets a little itchy on the arms and seat after a few hours.  

Pros: great value, headrest and movable arm rests.  good height adjustment and easy to assemble
Cons: mesh covering on seating and arm area can irritate after a little while, would also like a little more padding in the seat.