Mega Man 9, Mega Man 10, The Beatles Rock Band, WarioWare D.I.Y. Showcase, Final Fantasy IV: The After Years, and some other stuff all have DLC. Mostly they only have DLC for WiiWare games, since buying a WiiWare game confirms that you have an internet connection. If you buy a disc at retail, there's a really good chance you don't even have your console connected to the internet.
But yeah... I don't miss it at all. I like complete games. Instead of buying a level pack for New SMB Wii, I'll buy Super Mario Galaxy 2. Win/win.