1) Your power supply is nowhere near enough to handle a GTX 970.
2) That i3 will hold a gtx 970 back. you will be spending more and getting less performance than you should. Might as well just get a downgraded card like a GTX 960 if you are going to stick with this machine. Still recommend upgrading that power supply though.
3) That build is very low budget. If you are looking for a machine to hold up to today's standards, you are best off buying a totally new machine. The only parts i'd suggest keeping are the hard drive, case, and cd/dvd drive. Even your ram is not optimal since you are running different speeds and separately purchased sticks.
one of the best solid state drives for the money/performance are the samsung 850 evo drives. if you are looking for something a little more affordable the crucial bx200 drives are a good budget option.
keyboard and mouse come down to preference. one of the best mice on the market imo is the logitech g502. any good mechanical keyboard will do. razer blackwidow or corsair k70 are good ones.
you should try to stick with an IPS monitor over a TN or VA. you are looking at that benq which is a VA monitor. VA is more susceptible to ghosting and high response times.
http://www.tnpanel.com/tn-vs-ips-va/
for help picking a power supply use this guide:
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html