I bought my Wii on the day it launched, primarily to play Zelda: TP. Once I tore through that game, WarioWare: Smooth Moves was the only game I continued to play consistantly. I was pretty much bored with the system, and stuck to playing my 360. When a friend told me about the Twilight Hack, I installed the HBC just to play emulators on my TV. I already had emus on my PSP and PC, but I wanted to sit on my couch and play some Turbografx-16. The emus were buggy back then, to where you had to hold down the 1&2 buttons, and hope the emu booted to the menu.
Later on, my friend told me about WiiGator's backup launcher, and it sounded like fun. Just knowing it was possible, was enough for me give it a try. This is where I realized how fun hacking the Wii can be. It wasn't about the games, it was about getting things to work properly, and following directions carefully. I've been following the scene ever since.
For the DS, I got an R4 because I wanted emus on my DS, plus all the cool homebrew/music apps that I read up on. I have quite a large collection of actual retail games, and it was nice to carry them all on one cartridge wherever I go.