I would normally install Windows 7, but I'm concerned about drivers. I can put on W2K8 R2, but do I really want/need to learn and have yet another incarnation of an OS in my house to support? (I've got machines with XP and Win 7 already). I just use my server for FTP, HTTP, file serving, media streaming, etc. But, if I could get away with a Windows 7 install, it seems like one less OS for me to learn the little details about.
"The PE T110 is a server, and as such supports server operating systems. This doesn' t mean you can't run a client OS on it, but it may be difficult. If the device manufacturer (Matrox in this case) does not have a W7 driver, then you can use the 2008 R2 driver. The 2008 R2 driver, as they are based on the same kernel, will work in nearly every case, unless the driver install package does an OS version check. If it does a check for 2008 R2, obviously Windows 7 will fail that check, but many packages do not do that."
2008 R2 is not so different from Windows 7 - you can even install the Desktop Experience feature and it will look like Windows 7. the only real difference you might see is in FTP. I have not actually setup FTP on 2008 R2 yet, so I can't speak to the specific differences or problems you might run into, but they do have updated FTP server software in 2008 R2.