I've seen original Xbox consoles in nice condition at Goodwill for $40. I collect different game consoles and older games too, and the original Xbox is still a great system. People are too quick to discard old systems and even ditch all their games the second a new console comes out.
An original Xbox is well worth the $40-$50. I still play my original Xbox and games like Halo and KOTOR still look great.
I'm not planning to get rid of any of my consoles, even when I buy the next round of upcoming consoles.