With Fallout 3 using the Oblivion engine, how much of the gameplay mechanics are also carrying over? For example, will enemies and their loot level up with the player character as in Oblivion?

A few gameplay mechanics will feel similar, I'm sure. We've been able to iterate a few times now on the whole "big open world" style of game. So there are things that we feel work well in that context. That said, there's nothing that we won't look at closely to make sure it fits in with Fallout 3 specifically, and level-scaling is one of them. We've created tools that allow us much more control to tie the leveling into individual locations rather than making everything happen globally as with Oblivion. We're also not letting creatures level up their abilities with you; a Deathclaw will always be a Deathclaw.