Genesis or Dreamcast?

I saw some nice deals on a Genesis and a Dreamcast at a local shop yesterday, and I was wondering which I should get, and which games I should get for it..?

Poll-type threads such as this hardly tend to spark much discussion and if you read the board header and/or the floated threads you would know that they're not allowed in General Games Discussion. Feel free to ask for game recommendations in the designated floated thread. Thanks!