A good brand name motherboard to start with. At least mid range.
600 watt brand name Power supply.
8 gigs to 16 gigs ram brand name.
(opinion) Intel cpu i-7 series or mid i-5 series.
Add on sound card brand name.
If you can afford it Radeon 7800 series or higher or GTX 770 or higher.
Latest SSD hard drive for windows and Lotro. Traditional HD for other games/apps
What did I forget?
Officer of The Lonely Mountain Band
Whilst cooking for Elevensies, Tinki floors 2 Orcs with her frying pan and fresh caught fish. The frying pan critted for 18 hp and the fish was extra tender afterwards.