I have the DS, but I don't like it as much (too hard on my old eyes). Mostly I play my GC version. I use one of my towns for major time-travel since I've paid off my house, caught everything, and don't like any of the animals there. That's why I'm in Halloween now!
It's become my "collecting" town: I'm going for all the furniture sets, outfits, weird items. I've got bells to burn, baby!
In my newest town, I've got all my favorite animals (Rosie, Blaire, Spike etc.) so I'm very strict about playing in real time and paying lots of attention to them. I maneuvered those animals into moving there, so I don't want to lose them!
I actually love stomping roaches and seeing their little ghosties!
For Halloween this year, my son and I are going as our characters from AC! I've already bought everything -- just need to get sewing...
ETA: I just remembered that there is no Halloween on the DS.
Another reason I prefer the GC version. I'm also not sure if TT is possible either on that platform.