Given all the software I've installed since purchasing my Surface Pro, it's taken very little time to max out its meager 128 GB drive. Despite having 40 GB of documents and data offloaded to the microSDXC card, the system drive is still about 80% full -- and that's after making sure to delete expired demos and running Disk Cleanup with Windows Update Cleanup.
Storage space will definitely be less of an issue with my Surface Pro 2. I've doubled the storage space to 256 GB (although the system only reports 232 GB capacity) and I've signed up for the SkyDrive promotion for 200 GB of free storage for two years that came with the new tablet.
But I know myself. Before this painful transition to SSD's, there wasn't a hard drive out there I couldn't fill with my pack rat behavior.
So to be safe, I just purchased my first Surface Pro 2 accessory: a 64 GB SanDisk Extreme microSDXC card. This is the fastest microSDXC card on the market and certainly not cheap at just over $100. It's actually more than twice what I paid for the Ultra version that I installed on my Surface Pro, but I didn't want to create an unnecessary bottleneck on my new device in order to save $50.
Out of the box, the card is formatted as exFAT, which guarantees compatibility with cameras, Macs, etc. But in order for the files stored on the card to be visible in Windows Libraries, the card has to be reformatted as NTFS.
Andy Pollard has a great guide for reformatting your microSD card over at his blog, Southpaw, Right Brained. Also be sure to check out his post on how to ensure that your microSD card shows up in Windows libraries: http://southpawprints.wordpress.com/2013/02/21/surface-pro-sd-card-and-windows-8-libraries/.
As I begin to work more extensively with the Surface Pro 2, I'll update this post with my findings regarding real world speed improvements between the Extreme and Ultra cards. I hope I didn't spend $50 falling for marketing hype!