On small servers such as VPS servers we generally would set up a 512 MB swap partition, and a two GB /tmp partition (so you can secure it) and leave the rest as a single partition.
You'll have to watch the server carefully to make sure it doesn't fill up.
Minimum if you're going to use separate partitions you might want to try:
/ 500 MB
/var 5 GB
/usr 10 GB
/tmp 2 GB
<swap> 512 MB
/home <balance>
but that gives you a very small server. Which is why I'd do what I mentioned above.
Note: I'm not responsible if you run out of space.
Jeff