Ripped from my comment @ Buzzerblog regarding the Cube, here's how I'd like to see the Cube run:
1. Money Tree: $2k, $10k, $25k, $50k, $100k, $250k, $500k; keeps the money from going too high too fast and leaves open the chance of a special final high difficulty challenge for $1m.
2. Host: This may be the oddball pick, but I'm going with John DeLancie; better known as Star Trek's Q. Given the atmosphere The Cube creates, there is a, pardon the pun, omnipotence about it, and who better to host it than one who has played an omnipotent being? That and I believe John's Q-like anecdotes will keep the presence of the game mysterious, exciting, shrewd when necessary, and still very entertaining.
3. For the Voice: My initial reaction was Pat Kiernan (the questioner from Grand Slam, et al); but something tells me his voice may have to be distorted to be more ominous. Perhaps another person will take the spot, but as of now, that's who I'd like to see be the Voice.
4. The Body: Initial reaction: Either Kari Byron from Mythbusters or Morgan Webb from G4. However, if a buxom model must be used, at least get one that is into these sorts of games. No name comes to mind as of now, but I'm sure one will pop out.