alt Hacker NewsTop tier is still MarkMonitor. Last I spoke with them, they had a five-figure minimum spend, but the per-domain costs are competitive. That cost buys you proper named support contacts, etc.
If you look up the whois for microsoft.com or yahoo.com, that's who you'll find.
Five-figure minimum spend sounds pretty expensive for the vast majority of businesses out there. Of course, just a drop in the bucket for major brands.