cyberdork33 said: you don't even need a separate hard drive, just another partition.
sometimes the config files in home don't transfer well between distros... it may be a better idea to create a partition on the second drive and mount it somewhere like /media/storage and then make symlinks for the folders in your home folder like Music, Pictures, Videos. Like he said, some thing won't work between different distros. I used to have a separate partition for my home but ran in this very problem. I finally just made sure I had a partition I used strictly for back-ups. Before I installed a new distro or updated the current one, I would back up my home directory to the set partition. then after install I could move the configs as I needed. I eventually learned what i needed to back up and what I didn't.