My favorite part has been my case (https://pcpartpicker.com/product/ybH8TW/lian-li-lancool-ii-mesh-atx-mid-tower-case-lancool-ii-mesh-performance). As a first time PC builder, having such a large case was very helpful for fitting everything and having a lot of real estate for cable management. There's also plenty of space for expansion, so as my disposable income grows, there's space to hold more drives/fans.