Go with the i5 4460 and the R9 380. You won't find a better GPU in that price range, and that GTX 1050 you mentioned won't even hit half the performance of this Radeon card. Also, definitely upgrade your power supply. You need something around 500 watts; here is an Antec option from Best Buy (
https://www.bestbuy.com/site/power-supply-units/antec-500w-power-supply/ ). As for the motherboard, that’s up to you. Since you aren't using an overclockable processor, you don't need to worry about Z97 boards. H97 boards have everything a Z97 offers except for overclocking support—meaning they still support RAID, offer plenty of USB 3.0 and SATA 3 ports, and most include an M.2 slot. For instance, the ASUS H81M-K that Sandra Gomez mentioned is one of the cheapest, most basic options, and you'll likely be fine with it. However, if you have a case like mine with USB 3.0 ports, you won't be able to use them because that board only has two USB 3.0 ports on the back. If you want to use those front-panel USB 3.0 ports, a GA-H81M-D2V would be a better fit. Note that both of these motherboards only have two RAM slots, so your single 8GB stick leaves you with just one slot for an upgrade. If you want four slots, you'll probably need to look at a B85 board like the GA-B85M-DS3H. Ultimately, you'll have to decide based on your specific needs and, of course, the different price points for each board.