I've been using SSD for the C:\ drive on my machines for a few years now. I still use HDD for my D:\ drives for all data and media since it's cheaper for a much larger amount of storage.
Tip: Just install your programs on the C:\, everything else to D:\. I even re-point all my Desktop, Documents, Music, Pictures, Videos default folders to D:\.
I just created a folder on the root D:\ called DataFolders and moved them all per the instructions:
Moving Your User Folders