Honestly, I'd recommend for that price, I'd swap out the air cpu cooler for a closed loop water cooler such as a corsair H80 or H110i GT if the case has enough room. It will be much quieter and the cooling will be much better.
As for the SSD, you're going to want atleast 500gb (240gig minimum) even if it is just your OS drive, reason being is as it will also cache access data for your HDD and have the pagefile for your ram, it will take up quite a bit of space without the OS alone so your 120 gig easily turns into 100gig(?) with a constant heavy load (as your HDD will be parsing 90% of its information to the SSD and ram) meaning your SSD performance is going to be as fast as you're expecting or as fast as it should be.
Like you, I was running a 120gig SSD for my main partition but it very quickly becomes clear it's just not enough (even though I was using my storage drive for most of the applications and games) and as the SSD runs low on space, which it will, you'll start running into errors and crashes left right and center for your applications, even for programs installed on the HDD. One way to avoid that would be to make sure as an absolute rule of thumb to always keep atleast 8 gig free (same amount as your ram) on the SSD, which with all the workload of what you'll be doing will just become a juggling act of moving things back and forth from the HDD which is quite an inconvenience.
The other alternative would be to get a WD black drive instead of a standard high capacity HD (the seagate) as they are optimised for increased work loads so you're going to get better performance across the board if that's going to be your main storage file where you store and run most of your other applications and games.
If money isn't an issue for you, it doesn't make sense to half ass those 2 aspects (SSD and HDD) otherwise you'll inevitably find yourself buying a new SSD down the line anyway for performance as a gaming/application drive or as a bigger OS drive, so might aswell do it properly from the start.
So my advice is either get a bigger SSD, or if you're keeping the small one, swap the HDD for a WD Black HDD.
Other than that, the build is decent
