Underrated: 

[i]Skies of Arcadia[/i]

Back in 1999 - when Sega was still a somewhat reputable developer and possessed a modicum of creativity and passion for video games - a certain division of Sega decided that it would be an awesome idea to develop an RPG based around being pirates, not of the sea but of the sky - sky pirates, if you will. The result was a lighthearted, colourful and entertaining adventure with a plethora of happy-go-lucky characters who want nothing more than to roam the skies above the world. 

Naturally it doesn't quite go that straightforward and it isn't long before our band of air-faring rogues (the [i]Blue Rogues[/i] to be exact) are wrapped up in an adventure to save the world from the oppression of the Valuan Empire. Did I mention that the opening scene is more or less inspired by the beginning of Star Wars: A New Hope? 

[youtube]https://www.youtube.com/watch?v=eX7CmBeVTUU[/youtube]

You also acquire your own ship to navigate the skies and can recruit an entire crew of characters, and eventually establish your own base of operations. One of the best RPGs that not many people played unfortunately, and one of the better creations to come from Sega. The sequel will never happen though.

Overrated:

I'll probably post something about this later when I'm not quite so lethargic, rest assured there's no shortage of titles to choose from.