My layout is built to host multiple systems, without using LVM (because it would require me to learn something I would really rarely use in practice), with usually one system being rather minimalist: allows to fix others when I break things.
Except for this backup system where everything is kept on a single partition, I usually split each systems in: "/" and "/usr", and name them with partition-labels (thus GPT) like "${hostname}_{partitionrole}".
I use a /boot that allows both UEFI and legacy boots, manually updated and running [sys|efi]linux. It is also wide enough to host a CD iso, just in case.
The /home is shared between systems, and I do not use swap at all: swap only gave me troubles, and with this computer I have no need for it, those 16Gio are much more than I really need: as I write, with 2 VMs running and a web browser, `free` reports 8Gio free, which means not even used for cache! JFYI, I also disable overcommit, so that my computer's behavior is pretty predictable, even if that's out of topic.

I keep the space I don't need unallocated, and the amount varies with the size of the disk, of course. Depending on situation, I sometimes have a separate partition for "big files": mostly music, disk images, VM disks... I mostly do that on mechanical disks though, where fragmentation and physical location of files might impact performances (no measurement here, just old memories) and to keep things a bit easier to move around. I should probably also move compilation stuff on a specific partition, since this tend to take a lot of disk space and is distro-specific. This would imply tweaking my system a bit to be smart about it, and that projects would not rely on stuff that can't build out of tree: for now I only know how to do that with cmake, makefiles, autoconf or scons, I have no idea how to do that (without hassle).

My current disk is a 250Go SSD:

Quote:NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 223,6G 0 disk
├─sda1 8:1 0 1G 0 part /boot/part
├─sda2 8:2 0 2G 0 part
├─sda3 8:3 0 20G 0 part
├─sda4 8:4 0 18G 0 part
├─sda6 8:6 0 30G 0 part /var
├─sda7 8:7 0 100G 0 part /home
└─sda8 8:8 0 20G 0 part /

There are 2 empty spaces here: one of 20Gios, another of ~12Gios, not shown.

And to answer the questions about the system partition sizes:

Quote:/dev/sda8 20G 7,9G 11G 43% /
/dev/sda6 30G 4,9G 24G 18% /var
/dev/sda7 99G 81G 13G 87% /home
/dev/sda1 1022M 63M 960M 7% /boot/part

Most of my /home space is used because 1) it's a mess, 2) multimedia files + ISOs and 3) VMs disks.
I plan to build a software RAID on this system, and have the disks, but this is still on my TODO-lists, notably because I need to build a box, currently the motherboard just sits behind the screens :S