From a recent Bungie.net article Roger Wolfson, a Bungie programmer, spills the beans on "Bungie Pro".  It's a 750pts/year subscription to give you extra storage space for your saved films, game and map variants, screenshots, film clips, and more.

The current plan is that everyone with a copy of Halo 3 and an Xbox Live Gold account gets 6 slots where you can place up to 25MB of these files to share with the world. Saved films take up the most space, and 25MB should be enough to hold several longish 16-player games.  We don't think the average user will be hurting for space.

Inside your file share, you'll find a button that will lead to an Xbox Live Marketplace panel, offering you a one-year "subscription" to Bungie Pro for a planned 750 Points. Buy this, and for the following year, your file share will balloon to 24 slots and 250MB. At the end of the year, you'll be asked to either re-subscribe, or else bring your share back under the default limit before you can upload new content.

Summary:

• XBL Gold gamers will get 6 slots and 25 MB of storage space.
• You can upgrade to Bungie Pro which will be 24 slots and 250 MB.
• Silver gamers can get Bungie Pro.
• You can browser file shares in-game and at B.net.
• You can pass around URLs to file shares.
• You can click on a URL at B.net and queue a download for your XBOX 360.  The download will begin once you boot up HALO 3. 
• You can download up to 8 file shares at one time.
• You can save screenshots and have them viewable at B.net.
• You can save more than 6 (or 24) file shares to your hdd.  But, online the ones that you share out can be accessed by others.

What do you think about the extra storage space?  At about $10/yr, is it worth it?  Do you think Bungie will offer more incentives to get a Bungie Pro account?