Before we dig into what the differences are, you can sign up at Microsoft Connect or at the Office 2010 Beta page and you too might be able to get your hands on a copy to test yourself. The Office 2010 Beta would be the best bet, but for those in good standing with previous Microsoft Connect tests you might have better luck there.

The first major change to Office 2010 is the availability of both 32-bit and 64-bit versions of every application. Not just Excel or Access, the entire suite including Visio will be available in both flavors. The catch is that anyone currently running a 32-bit copy of Office will be forced to completely uninstall that prior to starting the install of the 64-bit flavors. If you wish to load the 32-bit version of 2010, it works just like every other upgrade of Office from 97 on up to 2007.

For the purpose of this review 64-bit Office/Visio 2010 were used on a 64-bit copy of the Windows 7 Ultimate RTM.

Office 2010 weighs in small with the 64-bit suite coming in at 612MB, and the 32-bit variant coming in at 548MB. Visio 32-bit and 64-bit weigh in at 300MB and 350MB respectively. The actual size installed is larger, but the installers are quite small and on par with the size of the 2007 installation media. Attempting to install the complete suite of Office 2010 64-bit with all features will cost you a respectable 2.24GB of disk space. Visio will cost you an additional 1.32GB of disk space. For the full requirements list, a screenshot of the Microsoft Connect page has been included.

The install itself will take roughly 4-7 minutes to complete on a 7200RPM drive, which is about what Office 2007 took on a similar system. Worth mentioning is Microsoft’s silly feedback program associated with the Office 2010 preview. It's called "Send-A-Smile" and quite literally you can click to send them a smiley face or a frown face based on your experience. Both faces appear in your taskbar and can be closed out. By sending them feedback it will default to sending them a screenshot of all connected displays so be careful about what you have up before submitting it. There is a checkbox in the lower left corner of the popup window to disable sending them a screenshot for those concerned with privacy.

To start off with, the splash screens to start any of the applications now includes a minimize and close button in the top right corner of the artwork, likely for slower systems or in the event of a problem you may not have to resort to task manager every time. This should bring improved help to average users who may not immediately consider task manager when there is an issue.

With Word being probably the most used application in the Office suite, it was first on the list to open and explore. Right away you will notice a new icon added just below the location that in Office 2007 included the orange start pearl. This icon was also added to Paint and WordPad in Windows 7, this seems to be the new standard. Clicking on it will being you to an interesting menu that will serve as a highly visual version of the File menu did in Office 2003 and earlier. It will also serve as your options menu for configuration and updates. Each line item on the left navigation panel will populate the center page differently. In the case of printing I think most of you will find it a welcome improvement. No longer will you need to play around in the preferences window to double side or change page settings. It is all right there on the page for you. This menu is included on every application within the Office 2010 suite.

The next is a welcome change for many. The Ribbon is now highly customizable. Whereas before you could manipulate the existing tabs, with 2010 you can now create your own tabs from scratch and populate it with whatever you want. In the screenshot I created a tab called "AWESOME TAB" and populated it with some fairly useless items. However you can choose to populate it with any item available within the 2010 ribbon, allowing for power users that want specific features and shortcuts normally available on different tabs and sub-tabs to build their own super tab with everything they want in one location. Within the customization you can click and drag the ribbon tabs on the right panel up or down to reorder them according to your personal preferences, ensuring that your custom tabs appear first each time you open the application. Again, this is available on all 2010 applications in the suite.

For Visio 2010, it too has been given the same advancements to the UI and ribbon as the rest of the Office 2010 suite. Aside from that Visio feels much like it did under 2007 so Visio users should feel right at home in seconds.

Outlook was due for a major overhaul and it got it. With 2010 the number of new features is staggering to an end user. First up is the Ribbon -- yes Outlook 2010 has a Ribbon and does a good job or organizing it in a way that doesn’t clutter the UI. The second major difference is that all emails are thread based now. Replies will go under the major subject allowing you to see all the actions taken as part of that thread. Clicking on the thread will expand it to show each email received on that subject. You can take it a step further and expand the thread itself to show each of your outbound items also linked to that thread. Clicking on an outbound item will even draw a line to the memo it was in response to. This is a major time saver for those that deal with the typical workplace email threads that go on for miles. Instead of “threads” Microsoft chooses to identify them as “conversations” likely in response to Google Mail which labels them in the same way. The mail icon left of the sender field will display as multiple envelopes to indicate there are multiple memos as a part of the "conversation" as opposed to a single email on its own.

For those of you concerned about Outlook 2010 64-bit and the requirement that you first uninstall your Outlook 2007 32-bit edition have no fear. As long as you leave the PST files alone in the location they were located at for 2007, then they will be automatically imported the first time you launch Outlook 2010. The entire process took all of 30 seconds with 3GB in PST files in play. Indexing will take slightly longer but it will occur silently in the background while Outlook is running.