Commercial Options
Telerik is debatably the best out there right now, and they put a lot of money into supporting the community by sponsoring podcasts.
DevExpress is comparable. They have a lot of skins and I've had good experiences with them in the past.
Both of them have WinForms packages that come in at $799.
Nevron UI ($169) and DotNetBar ($264) are also options. But you get what you pay for, and some of the free options below are worth looking at before spending money on these.
Free Options
WPF is Microsoft's next-gen presentation framework, and it is extremely powerful. It all the features you're looking for and more, although there is a substantial learning curve.
Krypton gets the job done and it's free. It's mature, easy to use, and they continue to updated it. Plus it has a bunch of built-in skins, including some good Office-style skins. I will say that next to WPF it's looking dated. But that goes for most everything.
