This channel would show leaderboards for every leaderboard-enabled Wii/Wii-Ware title you have played. You could customize the page by moving the leaderboards around or ranking them by which leaderboards are most important to you.
You can see which of your friends are online and text chat with them via a USB keyboard.
You could access your music from SD flash cards and play it with a Wii music-player. Support for larger SD cards (8gb - 16gb etc.) could be offered via a system update. (What is the current limit anyway? 2gb or 4gb?)