wow, epic fail for "priiloader" to be selected as the best answer to brick-proof a wii
#1 best protection, bootmii @ boot2. With this and a nand backup u can recover from any software related problem using just an SD card. Even on a wii that's never been hacked before and doesn't have a nand backup, if it's old enough to have a vulnerable boot1 (ie. able to install bootmii @ boot2) you can fix any brick using an infectus chip.
Second best protection, is just having a nand backup. With this u can recover from any brick using an infectus modchip.
Priiloader is also great protection, allowing semi-bricked wii's that could only install bootmii @ IOS to access bootmii to restore a nand backup without requiring an infectus modchip. And having priiloader installed will allow u to recover from just about anything as long as the system menu IOS and the system menu (including priiloader) are intact. Warning about priiloader, installing a new system menu overwrites priiloader.
In short, the best brick protect is always a combination of bootmii@boot2 (if possible), bootmii@IOS, nand backup and priiloader
There is also some merit to fatherjack's response. S/UNEEK is an excellent way to test the pirated crap you might find lurking on the internet... but that isn't really brick protection the same as abstinence isn't really birth control.