I have found it can also depend on what distro you're using. I usually do the following (on a 128GB SSD)
500MB - /boot
5GB - Swap Partition
50GB - /
70GB - /home
/boot doesn't need to be any bigger than 500MB
Swap is up to your discretion if you even want to use it. I have 16GB of RAM, so I doubt I use the swap too much. But I like to have something there just in case.
Your /home directory is where all your Pictures, Music, Videos, etc go (by default, anyway) so that may likely be your largest partition.
Your root directory (or just / ) kind of depends on how many apps / games you intend to install. You can tell something like Steam to install to /home or do a secondary drive with a larger partition. But by default most programs will take up space on your root directory, so plan accordingly.