This is a simple (as in 'not bloated') and solid Google Maps plugin. It allows you to add a map to a (custom) post, and show that map in your templates, optionally with geocodes. You can also create a map mash-up and use your own custom markers.
The plugin is also well-coded and stable. The code examples make it easy to integrate this into your own theme templates (be sure to read a few support threads!).
It´s not as full featured as other maps plugins so make sure this plugin offers everything you want (eg directions are not included, maps are not responsive).
Big thanks to the authors!