For your budget, I would suggest a cheaper I3-6100. Even a I3-6300 or i3-6320 would be cheaper.
Most of what you do will not use more than 2-3 threads so the i3-6100 will be faster.
Here is a review, Compare to the slightly stronger I5-6600 which is used as a comparison.
http://www.anandtech.com/show/10543/the-skylake-core-i3-51w-cpu-review-i3-6320-6300-6100-tested
I3 does well because of the higher individual clock rates compared to the quad.
You can use any LGA1151 motherboard. The H100 chipset will be the cheapest.
There is nothing that a more pricy motherboard will bring.
Ram is very good, as is the Seasonic psu.
I will never again build without a ssd for the "C" drive. It makes everything you do much quicker.
120gb is minimum, it will hold the os and a handful of games. If you can go 240gb, or 500gb you may never need a hard drive.
I would defer on the hard drive unless you need to store large files such as video's.
It is easy to add a hard drive later.
Samsung EVO is a good choice for performance and reliability.