With the rolling aspect of LMDE, I would still keep at least a separate /home partition just in case you ever have to reinstall the / for some reason. There may be an unforeseen disaster, and a reinstall may be your best option.
I use a separate /data partition instead of a /home. They are very similar, so either choice should work for you. I like having the safety factor.
Linux Mint Xfce 64-bit and Debian 6 "Squeeze" GNOME 64-bit