I bought an i7 6700 4MHz  Envy w/16 RAM  128 GB SSD and 2 TB Hard disk, I opened it up to install a TI Firewirecard and there were NO slots other than the video card. Needless to say I was blown away since there were slots on the case. So its going back to Costco and I ordered  
1 x Phanteks Enthoo Pro Series PH-ES614P_BK Black Steel / Plastic ATX Full Tower Computer Case
1 x Thermaltake SMART Series SP-550PCBUS 550W ATX 12V 2.3 SLI Ready CrossFire Ready 80 PLUS BRONZE Certified Active
1 x Cooler Master Hyper D92 - CPU Air Cooler with Dual 92mm Offset Push-Pull Fans and Accelerated Cooling System
1 x Intel Core i7-6700K 8M Skylake Quad-Core 4.0 GHz LGA 1151 91W BX80662I76700K Desktop Processor Intel HD Graphics 
 1 x Seagate Barracuda STBD2000101 2TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive Retail Kit 
1 x G.SKILL Ripjaws V Series 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 2133 (PC4 17000) Intel Z170 Platform / Intel X99 ...
1 x Microsoft Windows 10 Home - 64-bit - OEM
1 x Intel 535 Series 2.5" 480GB SATA III MLC Internal Solid State Drive (SSD) SSDSC2BW480H6R5
1 x ASUS B150 PRO GAMING/AURA LGA 1151 Intel B150 HDMI SATA 6Gb/s USB 3.1 USB 3.0 ATX Intel Motherboard
 
Have not built a PC since my Q6600 nine years ago. That just could not run without dropouts and issues. 
 
Given that the SSD Drive is nearly 500GB Should I keep all samples on it or still install them on the second drive? This is my first PC with an SSD.(It was fast on the HP)

Hi. I did this last year (the day after Win10 became available last summer). Went through Win 7 to 10. I am still on Win10, an I am loving it. Just be sure that your hardware is compatible with Win10 (drivers etc). Other than that, it has been solid as a wood burning stove for me I have all SSD's in my pc, and could not be happier. I have projects, samples and OS on separate SSD's.
All the best. 
Edited..

im not a sample hog (I don't have gis and gigs / TB and TB of samples.
I probably have 50GB in (non cakewalk) samples.
I keep these on my C drive with my OS, which is a 220GB SSD Drive)
its as fast as lightning.
im in the process of a new build myself.
an I7 4790K with 16Gb of ram.
I was very close to purchasing the new AMD 8 core 8750. but decided to go intel this time.
ive been using AMD for almost 7 years now exclusively and have been very happy.
but im not in to gamming or in to over clocking.
im just excited to see what everyone else is bragging about with newer intel processors.
been a while since I went with a new one. (even the 4th / 6th gen's.)

YEah I really don't use VST instruments. But  have still had drop out issues on a Q6600 Dual Core.
 
I am hoping my build will encourage the use of Dimension Pro and Synths.  My Hardware has great sounds. Especially the Tyros. But I can see me using the Garrington string set

I did almost this exact upgrade just a few months ago. I did and still keep my drives like this:
 
C: (SSD drive): Win 10/64
D: Samples (for virtual instruments) and project files
E: Audio samples (for sound design) and SONAR project audio files
F: Backup drive for imaging C and backup of my SONAR project audio files and project files
 
I don't use per project audio files "per se", but instead have an "Audio" folder on E and each projects audio files in their own folders inside. So, basically I keep the actual project file separate but otherwise it's split per each project. This way I can look at project files only and organize them based on project or whatevz, but all the audio for all projects is in its own place.
 

...wicked
I did almost this exact upgrade just a few months ago. I did and still keep my drives like this:
 
C: (SSD drive): Win 10/64
D: Samples (for virtual instruments) and project files
E: Audio samples (for sound design) and SONAR project audio files
F: Backup drive for imaging C and backup of my SONAR project audio files and project files
 
I don't use per project audio files "per se", but instead have an "Audio" folder on E and each projects audio files in their own folders inside. So, basically I keep the actual project file separate but otherwise it's split per each project. This way I can look at project files only and organize them based on project or whatevz, but all the audio for all projects is in its own place.
 

 
Just built my new Rig after a DOA Motherboard. Chose 500 GB SSD with 2 T back up,
Since my SSD is 500GB I was able to install all programs, EFX,and samples on the C drive.  Still have well over half left. Using my D drive for bundles back up projects, an E drive is Drop box only