Well, I'd recommend the basics, like your Marios, and your Zeldas, and your Mega Mans. Duck Hunt is always addictive if you can get it. I've been having a lot of fun with Punch-Out lately. Kung-Fu is pretty good as well. Brings back memories, that one does. Final Fantasy... I spent $50 on eBay for it this past January (I made sure it came with everything it was originally packaged with, that's why it cost so much), and that game is really fun. Paperboy. Mmm. Fun but frustrating.

Well, I hope that helps you out.