X8 might not be all that great, but it's a step in the right direction.
The story: Whaddaya expect? It's a Megaman game. Only this time, things are a bit different. Humans have begun to move to the moon in what is known as the "Jakob Project". Vile (Sigma lackey extraordinare) has kidnapped (or would it be "robonapped"?) new-generation reploid and Jakob Project leader, Lumine, so that he, Sigma, and various other followers can begin a conquest of the moon. Now X, Zero, and Axl must fight 8 Mavericks, Vile, and Sigma in order to rescue Lumine.
The gameplay: It's better, but still has some problems. The annoying switching from 2D to 3D mid-level aspect from X7 has been removed. There are only two levels with 3D action, keeping (some of) the frustration to a minimum. The dual hero system from X7 returns and has been revamped. Not only can you switch between the three to utilize each's special abilities, but now you call in your partner to bail you out when trapped by an enemy and perform devastating "Double Attacks". The level design has gotten better and that classic "Megaman" feel is still there (8 bosses, you take their weapon, etc.)
The graphics have improved since X7 but the character models kinda tank. Maybe they should made em more like the one's from X7...
The musical score is great as it usually is and the sounds and voice acting are much better than X7. The audio is probably the best part of the game.
Be warned, though, the game is very frustrating. This could be the hardest game in the series, behind 1,6, and 7. I will say this: Megaman X8 is ambitious. It falls somewhat short of its goal, but it makes me wish that Capcom would get off their lazy butts and make another sequel...