well you can search this forum for "partition schemes". There are dozens of threads out there.
Here's one that I recently posted
. I will only say it all depends on your needs present and future.
For quick reference, here's my scheme
/boot - 100 MB
/ - 14 GB for slackware
/swap - 1 GB
/home - 56 GB
/ - ~10 GB for Ubuntu
/ - ~10 GB for Arch Linux
free space - rest of it for future distro/s.