Those two tend to be related. It really angers me every time I see a huge amount of whitespace for no good reason, but then most of the functionality is hidden behind a dropdown menu whose equally stupid '...' indicator only shows up when you happen to hover over it. WTF.
Back when UIs were still good, things would usually be hidden only if there wasn't enough space. You could see almost everything you needed at a glance. The "designers" dismiss that as "messy" and "clutter", which is frankly absurd --- something functional is not going to look "clean", much like a machine shop that's in active use: Tools and parts are laid out everywhere, because the user needs access to them.
That diskprices.com site is great. Craigslist is another one that comes to mind. The only thing it's missing is a "submit" button for those who have JS disabled... otherwise it's a perfect example of extremely functional design that wasn't ruined by "UI/UX designers".