As an engineer I know that making things smaller costs money, and generates more heat in a smaller space. Either you get cheap parts OR too much heat OR overpriced systems OR big, heavy (not-portable) chassis OR some combination of the four. We have PSPs, DSs, Smartphones, etc for a reason.
- If you have money, get a good desktop. You can always get new, "cutting-edge" hardware as it comes out.
- If you don't have money, get a cheaper desktop. You will save money fixing 1 part then scrapping the entire thing if something ever does break-down.
When I'm traveling I don't have time to play any big games; plus quick, casual games work fine on cheap laptops.