I don't think there's been an update to the Wii since Wii Menu 4.3 came out a while ago.
All the homebrew you need, including the Homebrew Channel, Bootmii, WADder, IOS Patcher, Emulators, etc, work perfectly on the current firmware, and it'd be unlikely that Nintendo comes out with an update to the old Wii.
Having had all of this homebrew since Wii Menu 3.3, I'd say it works quite nicely and is easy to reinstall, as Wii softmodders respond to the simple coding of the Wii very quickly and are able to patch their respective Homebrew quickly. So even if Nintendo does update their firmware, which I doubt, new versions of the hacks will be out soon.
If you have Smash Brothers, Smash Stack is a great way to get started with the Homebrew Channel. Then load up some Trucha-Bugged IOSes and get the Homebrew Browser (Which is a great way to browse most of the apps for the Homebrew Channel) and you'd be good to go.