Ubuntu – Installing Ubuntu on a SSD and HDD system

First of all, the root will not likely take more than 5-10GB; even if you plan to store loads of programs, 15GB should be enough. So you still have plenty of space left on your SSD.

SSD is faster when making random access -- for example, accessing a large number of data base records or reading loads of small configuration files. I'm not sure to what extent putting /home on SSD speeds up the responsivity of the system; it will sure play a role if you plan to use wine and install the Windows programs into your home directory. Moreover, hard disk can have better transfer rates -- so reading a large, continuous file from an unfragmented HD can be faster.

Given that you have plenty of space on the SSD, you could set up a separate /home partition on your SSD (by all means, use a separate partition!), and use the HD to store large media files (movies, music, photography, archives, data). At least that is the way that I manage the things.

Swap partition might come in handy if you have a laptop and would like to have the option to hibernate -- the memory snapshot will then be saved to the swap partition.

I think your plan is OK but while you are at it, why don't you put the /var on a Logical Volume too instead of a separate partiton on your new drive? I find lvm a lot more flexible than regular partitions. My main machine is all using lvm, including / without any problem and very quick to resize/reconfigure Logical Volumes.

To use your current HD with lvm, you'll need to empty and format it. One way to do that is to put the new drive as a device in the Volume Group, move your current home to it, format the current HD and add it to the VG.