With 120GB of SSD, that's alot. I'd still install ALL your added programs to the SSD, for fastest access and loading.
Upon install of added programs, you can choose where to install them.
I'd move your "Libraries" to the HDD: My Documents, Downloads, Music, Pictures, and Videos. Just drag them fron the C;/Users folder to D;/.
With an Intel based motherboard amd Windows 7, I'm sure TRIM is enabled.
You can download "Garbage Collector" from OCZ, to clean up the SSD, when the need is felt.
Great build, BTW!