The Odyssey 2 I would say is a great budget vintage system to collect, and has several games for it that are still fun to play.
http://www.classicgamecreations.com/ordering.html
The multicart with all the classic games on it is cheap and worth picking up.
gooddealgames also sells some homebrew games for the system.
A must have? Not really, but it is fun cheap classic console that has a small and growing following. It makes me smile to know that there are collectors out there wanting this system still!