Almost a year ago we highlighted FoxTube, an alternative YouTube replacement for iOS that filled in a lot of missing gaps. And even though Google's own YouTube app (iTunes link) has replaced Apple's and delighted many users, FoxTube is the non-Jailbroken power user's player of choice, offering extra playback controls, media information on the lock screen, and the ability to play media in the background.
While I'm personally happy browsing YouTube on the web and using Tube Controller to integrate my Mac's media keys, FoxTube has come to the Mac, giving anyone the power to download videos offline for later viewing, take advantage of advanced media controls, and play media through a convenient mini player. In contrast to many recent app launches for OS X, it's even available for the latest version of Lion. FoxTube for Mac is $9.99, but you can download a free trial from the developer's website. Due to restrictions on the App Store, I'd recommend purchasing the app from the developer to get the full set of features.