I'll leave it to others to recommend mobos and other internal components. I want to recommend a mechanical keyboard with brown switches. If you type a lot, it really makes a difference, IMO. I love the way it feels.
I have this one, but there are lots of different brands at different price points. If you live near Micro Center in Overland Park, you can go in the store and feel the different types of mechanical switches in case Brown isn't the one for you.
