@twesterm - I'm sorry, but if I had to choose (and I won't, I'll get both), Bioshock is comin' home with me. Once I heard there was a spiritual successor to System Shock 2, I knew it was all I ever needed or wanted in life, ever. And I love Metroid.
@stof - If people can't find a certain item/room/switch, it'll be because they're a bit slow, and not any fault of the game design or designers. These guys know what they're doing; I'm sure there'll be some navigational assistance. Not that you were necessarily suggesting otherwise, but just felt like clarifying.
@IllegalPaladin - You must be excited about this game! Immediately! If you like first-person shooters with ingenious combat scenarios and RPG-stats/upgrade systems, you'll love this. And wait 'til you hear what these people can do with sound: ambient, creature voicework/sound-effects, etc. System Shock 2 was just downright frightening, and now Irrational has a budget like they never have, with 2KGames backing them, so the graphics are finally top-notch as well. Ken Levine is brilliant, and I'm so thrilled that he's finally in the spotlight with this project. The world will see what Irrational's really made of.
@libellule - Forget multiplayer. If you want a single player game, then get Bioshock. If you want multiplayer, play a game that specializes in it. I wouldn't want to play a crummy, tacked-on multiplayer mode for any game that had a solid-in-itself single player experience. If lack of multiplayer causes the downfall of this game, I'll eat my hat.
"Whenever you find a man who says he doesn't believe in a real Right and Wrong, you will find the same man going back on this a moment later." -C.S. Lewis
"We all make choices... but in the end, our choices... make us." -Andrew Ryan, Bioshock
Prediction: Wii passes 360 in US between July - September 2008. (Wii supply will be the issue to watch, and barring any freak incidents between now and then as well.) - 6/5/08; Wow, came true even earlier. Wii is a monster.