I stumbled across the Retro Roms blog today. This is a great site that focuses on new games for retro hardware. It also has some great general posts on the subject.

Here are a couple of the ones that kept me around longer than I have time for:

Dr. Mario For the Atari 8-Bit computers

Geometry Wars for the TI-84 Plus

Pitfall for the TI-99 4/a

His Dark Majesty – an incredible RPG/RTS combo for the Atari 8-bit computers

There certainly is a lot more on this site for any retro game fan.