Kiss your free time goodbye.
Now the question to most would be "is the gameplay good enough to put all this time in?" Ultimately that's up to the individual but I've done it dozens of times. Nothing in the gameplay is particularly amazing, but nothing's broken either. If the missions, enormous environment, rewarding exploration and overall story were'nt so good, the gameplay would likely just bore you. However with the incredible package here, just adequate gameplay more than does the job. At one point I made a personal quest to collect skulld around the game to decorate my house. This added a good several hours of gameplay as I snacthed up available skulls while on missions.
Again it's difficult to explain the magnitude of this game until you play it yourself. The world is HUGE! Think San Andreas, but without so much useless territory. It's hard to walk 100 feet in any direction without running into something to explore. This does pose a problem because it's easy to get lost or sidetracked and there's no marker system to help get you where your going. Then again, they didn't exactly have GPSs back in the medievel times this is inspired by. This makes it all the more rewarding when you do reach your goal though.
Now on to environment and variety. This game has both in spades. Each region of the map is drastically different and exudes a sense of culture all it's own. The small fishing villages will have a completely different feel from the bustling capital city, which will in turn feel very different form the wizardly island region and the desert planes to the north. Each town has it's own unique feel and layout yet will share a distinct style with it's region, truly making this seem like a fleshed out world.
All in all this is a must play game for anyone whose ever trudged through a massive MMO world or anyone with the patience to dig into this massive adventure. If you can find this game used or in a bargain bin somewhere pick it up. It does work on the 360 with a hardrive (by now you should deffinitely have a hard drive). And it shouldn't be more than 15-20$ used. I do recommend picking up the strategy guide if you want to delve deep in this monster though. It will save much frustration from navigating this amazing game.