What's the difference between Extra Virgin Olive Oil and Olive Oil? EVOO is far superior, and is in a natural state. Olive Oil has been processed, and is basically low quality oil blended with high quality virgin olive oil for color and taste.

Choosing between filtered and unfiltered extra virgin olive oil is simply a matter of preference. Filtered has a longer shelf life, whereas unfiltered has a more potent taste. This is due to  the microscopic bits of olive that haven't been filtered out.
Ravida Organic Extra Virgin Olive Oil ($49.95 Williams Sonoma) has a grassy, nutty flavor and is the only one I use.