What's up with that? I just was using my brothers iMac and noticed his Magic Mouse felt a little different while web browsing.. I went into the System Preferences > Mouse and realized that he had enabled the check box of "Scrolling" and had it set to "WITH MOMENTUM". So I figured out that was why mine felt different. I went into my System Preferences > Mouse and have the dialog box for "Scrolling" but I do not have the option to select "WITH MOMENTUM" or "WITHOUT MOMENTUM". I'm using a Macbook, and he has a new iMac. Both with Snow Leopard.. and I just ran a Software Update, and it says everything is Up To Date. Can anyone help me out? I don't understand why (with both systems up to date) would have different options in the Mouse Preferences. I really like the feel of the Momentum scrolling and I would like to enable it somehow.