Using 1 partition or 2 partition of each 1 TB on 2 TB drive ?

What is best to use on a 2 TB internal SATA drive ? It will be a boot drive.
- 1 partition of 2 TB (the UEFI partitions excluded)
- 2 partitions of each 1 TB (the UEFI partitions excluded)

I prefer reliability above performance on this drive .

There is not a big difference, but I personally prefer to devide such big sized boot drives into at least 2 partitions:
1. a smaller sized one for the OS (Drive C, in your case I would choose a size between 250 and 500 GB)
2. the bigger sized second partition for DATA (Drive D).
This way I have automaticly access to my important data, even in case of a later necessary fresh install of the OS.

Note: I have moved your thread into the "Off Topic" Sub-Forum, because your request is not Forum related.

you should describe with details your setup/hardware and what os you will install .

if it boots an other os on a other hd : then only boot sector [ first of hd is used… ]
the main question is GPT or not ?
as your hd is 2 To you can go MBR and have 2 To in one partition…

GPT seems better than MBR , so if you do not use linux , you should use it as much as possible .
as you do not care of size , may be you can check the size of plates of your hd : that should be 2 , 3 or 4 and divide 2To by this number .

if i were you , i would use a ssd with a small size 60-80 Go for the boot and windows …because it is not very cool to wait for hd to spin , at all time the os wants to read or edit boot sector or boot partition .
here are two models : a corsair 60 Go at 40 euros
http://www.ldlc.com/fiche/PB00209415.html

a kingston 120 Go at 45 euros
http://www.ldlc.com/fiche/PB00209415.html

that i would take…then you can install latest mint or ubuntu on it , it will shows your win hd at boot .
to make partitions for linux , you should use MBR , then create a mount point /boot of 2 Go then a /home partition that will have all files and hidden progs settings [ may be 60-70 Go ] and the rest in a partition mounted / that is the root of all folders of the os . if you have to reinstall then you only format /boot and /
if your pc is low in ram : 4 or 6 or 8 Go think of creating a swap partition on the ssd hd or an other hd like the 2 To [ you can set 8 Go ]