Your plan sounds fine, but you may run into trouble creating a fourth partition.
I may be wrong, but I believe that you are limited to only 3 Primary Partitions... but there is a way around that that I practice.
1. delete that existing partition you want to use.
2. create a new Extended Partition filling the available space.
3. create all the new partitions you want within the Extended Partition.
I believe the number of partitions is still limited but that number is Huge:
The DVD has Gparted on it, an excellent tool for this task.
While you are at it you may wish to reduce (or enlarge) the size of that other storage partition while you are at it.
I Have multiple installs and find that 10 or 15 GB for Root works just fine with a Home partition of 25+ GB.
Linux does not require the 65GB+ partition like Windows does.
I find a SWAP partition is unnecessary with more than 2GB of RAM... but I hear that some recommend Swap to be twice the size of your installed Ram. Mine is Huge at 24GB and I fine it is Never Used. I will probably delete it at some point when I need more space. I also have a secondary hard drive that I use for backups and storage and a couple other installs... it is partitioned in a similar fashion.
PS: You may have an existing tiny System partition that Windows created. Don't delete it! Problem is it will be counted in the number of Primary Partitions limitation. In that case it is time to move that Data into another area and revise your scheme.
My primary drive currently looks like this: http://www.use.com/b5df62ac1e00cfff3e37
PPS: that is a screen shot using Disk Utility... a great tool, and I use it to Label my partitions so I don't get too confused.