I priced a 1643-with FEL, 1 remote, loaded tires, 16 speed gear for $24295. Check Tractorhouse.com- they sometimes have prices that can give you a rough idea what things sell for.
On Aug 13th this year I got a price on a 1635L with cab for 35,900 (Canadian) but if that seems high, keep in mind we have to probably pay a higher delivery fee. More recently, I've seen pricing on 1643 with cab hovering around $30,000 USD which I think is a better buy over the 1635. For a couple grand more you get 20% more HP.