Unexpected beasties

I have three unofficial "pets" (two, if you count the fact that the third one scares me).

The first is a cat. He's been hanging around my apartment building for a few weeks now. He loves being petted and will even follow me to the laundry building. Once the weather starts getting colder, I'll need to call the local animal shelter, since I haven't been able to find a home for him and can't keep him myself without risking being evicted. It feels a bit like betrayal, since the shelter's extremely limited hours make it likely he'll be put to sleep, but I suppose that's better than getting frostbite. I keep hoping someone will steal him away, though.

The second is a gecko. The gecko lives between my dining room window and screen. I have no idea how it manages to find enough to eat, but it's been living there for at least two or three weeks. I say, feed on, gecko!

The third, the one that scares me, is a spider. It's fat and creepy, and I haven't had the courage to kill it. Thankfully, it stays in the corner behind my front door. I thought it was a black widow at first, but the colors are wrong. I've taken a few pictures of it - maybe I can find someone on campus who can identify it for me. I'm hoping it will turn out to be something that isn't harmful to humans and loves nothing more than to sit in its little area and munch on insects. Then I can continue to ignore it and it can continue to ignore me. At this point, just based off of pictures I've looked at online, I think it might be Steatoda triangulosa, but I'm in no way a spider expert, so I could certainly be wrong. I kind of hope that's what it is, though, because what I've read about that spider so far actually sounds pretty nice.