SSD for operating system and programs, normal hard drive for data.
I've done it on my desktop, running Windows 8 Pro no worries.
Done it on the laptop, moving the DVD drive to external, and installing a 2nd hard drive.
Boots fast, loads programs fast, excellent upgrade!
Work out how big the SSD needs to be to just hold your operating system and your program files, then add maybe 25%~30%. You don't need a huge SSD drive.
Cheers, and good luck with your upgrade!
Chris