Good question!
For local (home turf hunts)
Roe bucks - scull mounts. on plaque. (Made by me)
Small game animals, and birds - full mount.
Boar - tusks on plaque.
For Africa:
First, I had my list of animals I wanted to hunt, and bring home.
Then: I have chosen those that look most iconic, and most colorful as shoulder mounts.
The rest: european scull mounts.
After three safaris, it came down to 50% shoulder mounts, and 50% of scull mounts.
Considerations:
If for example, you choose to hunt springbok in 4 color variants - then there is no point in bringing them home as scull mounts. Need to be at least shoulder mount. Color variants go to shoulder mount without exception, or to single pedestal mounts.
If hunting Zebra for example, scull mount has no point.
Zebra will be full rag, or shoulder mount, or perhaps pedestal mount.
So, for some animals their colors (and lack of horns) make the decision.
Sable, roan? Most probably will be done in shoulder mount or pedestal mount, to emphasize the color of these fantastic animals.
Horns, tusks and antlers: If animal is known best for its horns, tusks or antlers - then scull mount can be considered. Kudu is antelope with longest horns in Africa, and in order to emphasize that quality, scull mount can be considered. Warthog, hippo, tusks display can be considered.
Small animal give opportunity for fanstastic full mount. Steenbok, perhaps.
Storage space at home is another consideration.
Smaller place - scull mounts.
Lower ceiling room, pedestal mount.
etc
Overall look of trophy room:
In my personal opinion, a nice trophy room should be split between rag, shoulder mounts, pedestal mounts, and scull mounts. Scull mounts to be placed on same type of wooden plaques.
This is my way of organizing things, but certainly not the rule.