Ubuntu – Installing programs in root vs home partitions

I'm a new Linux user and a Windows convert. I tried Ubuntu (Dapper Drake) a few years ago and liked it quite a bit, and I'm in the process of installing Xubuntu 13.10 along side Windows7 on my brand new SSD! At this point, Windows is still being installed because I need it to be, but Linux is getting installed because I want to use it! I've done quite a bit of research and I've toyed around with Linux before, but I'm still a newbie and I have a few questions concerning partitions and program installations..

My new SSD isn't huge (120GB Samsung 840 EVO), and I'll be using my old 800GB HDD as a secondary drive. The thing is, I plan on using Linux as much as possible; only switching over to Windows7 when I absolutely need to. Because of this, I'll be doing a 50:50 split of my SSD for each OS (60GB for Linux, 60GB for Windows). I'm also planning on splitting my old, 800GB HDD into 3 partitions: some space for extra linux programs, some space for extra windows programs, and then a shared NTFS partition for all of my data (music, videos, documents, etc.).

So to sum up my space situation:

• ~60gb SSD + 200gb HDD for Linux..
• ~60gb SSD + 200gb HDD for Windows..
• ~400gb shared NTFS..

This leads me to my questions.. While I have a fairly good idea of how my Windows setup will work (60gb C: drive, 200gb D: drive, etc.), the Unix/Linux directory structure is still very new to me and is making this process a little bit confusing. I know that it's possible (and common) to partition your "/" directory and "home" directory separately, and – as I understand it – the "/" partition is meant to contain system specific programs and data, while the "home" partition contains the programs and data of the various users.

However, I've also heard that most (if not all) of the programs that you install from repositories using APT are installed into the "/" directory. As someone who works with music/art programs and plays games (which can take up a LOT of space), this leads me to believe that I'll need a large "/" partition!

I've also read (from here: http://www.control-escape.com/linux/lx-partition.html) that the "home" directory is "the place where all the user-specific files, your data in other words, are stored. It is roughly equivalent to the “My Documents” folder on a MS Windows desktop". But, as I mentioned above, I intend to keep all of my non-OS-specific data (music, documents, videos, etc.) on my ~400gb shared partition, anyway. This really leads me to believe that I don't need a big home partition at all and that I should focus on partitioning as much space as possible for "/". And still, I've heard other people claim that you only need around 10gb of space for your root partition!?

Edit: Also, I just found out that programs like Steam and Wine take up space inside the "home" directory.

So, what should I do? I basically have 60gb SSD and 200gb HDD space for holding nothing but Linux programs. All of my data will be going onto my 400gb shared NTFS partition, so is it even worth making separate partitions for "/" and "home"? If I install both root and home on my 60gb SSD, how can I also use the extra 200gb of HDD space for more Linux programs? Can I expand root across multiple drives somehow, or maybe have a symlink or something that connects the two drives together?

As I said before, I'm still a major Linux newbie, so there may be something that I've completely misunderstood or overlooked. As someone who does a lot of art/music creation and gaming on my PC, I tend to use up a lot of program space quite quickly, especially since games and music libraries just keep getting bigger and bigger every year! Thanks for the help, I'm looking forward to learning more about Linux! :]