I have restored to 2 new HDDs and would suggest the following steps using 3 programs:
1) Windows Imaging
2) Macrium imaging Macrium Reflect FREE Edition - Information and download
3) Partition Wizard Bootable version Partition Wizard Bootable CD allows user to boot computer directly to manage partition.
1) Image C: (OS) with Windows Imaging to ext HDD
2) Image D: partition with Macrium to ext HDD
3) Remove old HDD Replace (ALONE) new (out of the box) 2TB HDD
4) Boot System Repair CD and reimage C: from Windows image.
5) Check new HDD boots
6) Boot Partition Wizard.
7) Resize C: into the huge unallocated space to where you want it.
8) Select remaining unallocated and create a primary partition and assign drive letter D:
9) Boot Macrium Restore disk
10) Restore old D: image to new D: partition; select not to replace MBR
You can use Macrium for steps 1) and 4) but Windows deals with the MBR and system reserve partition automatically. You need to do this manually with Macrium.
I would recommend against a 50:50 split. I would make the OS/programs more like 200GB than 1TB. You may then want to consider another user partition on a big disk like this.