Indeed^^^ Don't partition the system drive thinking it will give better performance as it won't(in fact, putting samples on the partition is likely to hurt performance as compared to simply putting the samples on C:). SSD for system drive? Yes(its a "no brainer")
Samples on a 3rd drive? Absolutely!
Re the SSD choices, I have both Samsung 840 EVO and 850 EVO and really don't notice any difference(they are both an excellent choice
). 2 caveats with the Samsung line. #1-the Data Migration utility works quite well, BUT, it will install the Samsung Magician software on the new clone, even if the source drive didn't have it installed. #2(why #1 matters) on my rig, the Magician software causes all USB drives to disappear(as in any drive connected via USB, like my Waves authorization pendrive and my drive that holds all my installers). Now this is not an issue in the long run because simply uninstalling Magician puts everything right back to working. If you load your new SSD from scratch(fresh Windows install, fresh PT install) you probably don't even need Magician. If you load the SSD from a drive image or clone it from a spinning drive, running the Magician software will boost performance(to where a fresh install will start). Once done, you can uninstall it anyway.
Quick recap:
SSD for system drive
7200 rpm spinner for sessions
7200 rpm spinner or SSD for sample libraries
smart add-ons:
large USB drive for saving drive images(if this is new to you, its something you need to get onboard with)
Large external drive for saving copies of every session that you really don't want to risk losing(there are 2 kinds of computer users; those that have had a drive failure, and those that WILL have a drive failure
)
1TB USB drive for saving everything you download(updates, Pro Tools installers, plugins, etc).