Very reasonable.
I have a few suggestions:
1. On ram, you should always buy ram in a matched kit. Two separate sticks is not guaranteed to work, for 8gb, buy a 2 x 4gb kit. The corollary to this is if you ever will want 16gb, it is better to buy a 2 x 8gb kit up front. Your motherboard only has two ram slots so you can not simply add ram later.
Other suggestions are preferences.
Love the G4600 pick.
Consider buying a 240gb ssd and deferring on the hard drive.
Samsung evo performs better and has a longer warranty.
240gb will hold a fair number of games and will make all you do be quicker.
If you want to buy a hard drive for windows, buy wd black; it is likely to be faster and more reliable.
RX550 is ok.
evga430 is tier 3 on this list.
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html
430w is fine for rx550.
But, your G4600 can handle a graphics card much stronger, and that would require a stronger psu.
Here is a psu sizing chart:
http://www.realhardtechx.com/index_archivos/Page362.htm
I suggest something in the 500w range.
I have no problem overprovisioning a PSU a bit. Say 20%.
It will run cooler, quieter, and more efficiently in the middle third of it's range.
A PSU will only use the wattage demanded of it, regardless of it's max capability.
Here is a tier 2 Seasonic S12II 520 w unit for a similar price:
https://www.newegg.com/Product/Product.aspx?Item=N82E16817151094
Lastly...
Buy yourself a #2 magnetic tip Philips head screwdriver for assembly.
While waiting for delivery, download and read, cover to cover the case and motherboard manuals.