SSD for boot OS/programs and two Samsung M.2 512GB M.2 drives in a RAID 0 configuration for data
Boot OS / programs - single Samsung M.2 512GB or Intel 750 (400GB or 1.2GB PCIe NVMe SSD)
Data - put all files onto a 4x SSD SATA RAID 0 array - pick a good brand and size the SSD drive size according to needs and budget
*** Best: (same Boot OS / programs setup as Better)
Data - Areca ARC-1883 series controller with 5 to 8 SSDs - pick a good brand and size the SSD drive size according to needs and budget
---> Backup is required however you go; don't skip it even if you go with RAID 5: internal & external (for off-site backup storage) - use whatever rotating drives you choose
Would you raid anything or is it no longer really needed?
if you don't mind raid, jim points out several examples. if you would rather avoid raid then it will depend on the codec's and projects. heavily compressed codec's like avc/h264 can work from a single sata ssd, or 2x sata ssd raid-0 using motherboard raid for more speed. if working with high bitrate raw or just wanting faster than sata ssd, a single samsung 950 pro m.2 drive will be fast enough to avoid raid. samsung will be releasing some 1tb m.2 drives if you need higher capacity.
I hate to disagree with a fellow forum member but unless you have extremely big projects which you said you do not typically do, RAID is not necessary today. For years I have personally used RAID and specifically RAID0 and been fortunate not to lose any data, but today with the immense speeds available it can be an overkill. I have tested the Samsung 950 Pro individually and in a RAID 0 configuration and have found it only increases the risk of data loss and does only marginal improvements with performance of Adobe Premiere and then really only for exporting. Now if you want to archive lots of data you may want it to be large, fast and fail-safe and then you do something like my dear departed friend Harm did in the past with his immense 24 each 1TB RAID 30 Areca array.
The difference in the export times from our PPBM Disk I/O performance shows diminishing returns as the write speed of the device goes up. I will shortly be preparing a report showing my results starting with an old 1 TB hard disk drive and going up to a 7 SSD array in RAID 3. It will include many in between devices and specifically a single 512 GB M.2 Samsung SSD and two of those devices in RAID0.
With the new devices on the market today and some just around the corner in the next month or so (how about a single 4TB Samsung 850 EVO SATA III drive now available for preorder) then there is the Samsung SM961 1TB M.2 drive that will be the fastest SSD ever delivered (first delivery sometime in August) and is the precursor to the 960 Pro SSD's. I have my order in for one of these OEM SM961 drives.
I can smoothly edit low end 4K (XAVC-S) on my lowly 4-core non-overclocked laptop off a USB 3.0 Samsung T1 external drive so if you install a new M.2 PCIe 3.0 x4 SSD that has 5x the read speeds in your 8-10 core much faster CPU equipped computer you should be able to handle any of the new higher resolution and more complex codecs without any problem