Installing wii channels is NOT dangerous if you do it properly.
You need to have your entire first page of channels filled as well as the first column in the next page.... these are the channels that are loaded into the wii upon reboot/restart.
You need to also have the homebrew channel on the first page.
Of course you should also have bootmii/priiloader/ect installed as a fall-back but they are not needed.
Install the channel via hbc..... if by some chance it's corrupted (and if you download it from a popular site it is HIGHLY UNLIKELY that it's corrupted or else people would complain) what will happen is your wii will freeze when you scroll to the next page.
This is a NON-ISSUE. You simply manually turn off your wii, go into hbc and uninstall the wad.
I'm not saying that it's impossible to brick a wii with a channel install, but it's quite hard to do so. I should know, I made many of the channel creation tools. BITD

The best option is an external hard drive. As the others have said, you won't be using all the room, but you can use the extra space for game backups. Most of the emulators are the "gx" emulators and they support loading roms from sd, usb, dvd, and network share. You'll be hard pressed to find more storage options for homebrew on a game console.