I guess this would fall under 'other pets'. This thread does seem to be cat heavy so far, but I am not fond of cats and am actually quite frightened of them. Unpredictable bitches.
Anyhow, I keep tarantulas. I have three, of varying species. They live for quite some time (if female, for decades), so they are not really a passive purchase, but they are good for apartments and are really cool to watch hunt. Otherwise, very quiet. Some visitors get creeped out, but learn to love them.
They are kind of like plants. You water them a bit, throw some baby crickets in, watch them grow. I don't know if I'd classify them as pets, because they don't really interact with me (although Sparkles knows when she is being fed these days) and do not require a lot of care (but these species more than some other tarantulas) .
I will steal OP's format because it's pretty good.
General Recommendation
Tarantulas are good for part time pet owners. They require far less care than fish, which I would compare them to, since you can't really play or interact with either. But they are still interesting in a behavioural sense and cool to watch grow.
If you wanted to start out, I'd recommend a Chilean Rose Hair (sold at most pet shops) because they are easy to care for and you can potentially handle them if you like.
Tarantulas take up very little room, only really need one good container for their lives (if full sized), a bit of water and crickets every so often.
Peculiar Tarantula quirks
Sparkles, my biggest spider at 2", has gotten quite good at hunting. She lives in a web tunnel and often tracks the cricket under neath her, trying to catch it through the back door she only uses for hunting. She stalks her prey and eventually grabs it in a blue flash. If she's asleep when I throw a cricket in, she will wake upon opening the container she lives in and be hunting in moments. She's caught crickets in mid air.
When Miss Cleo moults, she will physically move her old shell around her cage, away from her or out of her burrow. Cleaning house!
Food & water
When small, they just need a spritz of water or a few drops every other day to keep their containers moist. Any more, and they could develop mould in their booklungs or you could encourage mites (which killed one of my newly moulted spiders once).
Buying tiny crickets and catching them to feed to the tarantulas is the biggest hassle of keeping spiders. They normally like moving prey, and eventually I'd like to feed them cockroaches, but it's just crickets for now. Not sure if they will eat grubs.
You can't feed around a moult as their fangs will not be strong enough, and they could break one or be preyed upon by the cricket. This is normally only an issue at young ages.
Room temp seems to suit them fine now, with a lamp sometimes turned on to warm them a bit, since I live in Canada. They all live in pill bottles or similarly sized containers, with good air flow. Other considerations include straws for burrows, cork to build webs on and special substrate.
Miscellaneous
All my tarantulas are spiderlings. They are all under 2" in leg span, and the smallest is probably the size of one of your fingernails. Pictures of them would probably not turn out well, but I'll post what they will look like later.
Sparkles is my
Avicularia versicolor or Martinique Tree Spider. She's the largest one and eats everyday, like a pig. Right now she's a nice blue color, but later on may turn shades of red, green and purple. She's leggy and very fast and mostly hangs out in her web tunnel.
She will probably look like this:
Miss Cleo is an
Aphonopelma seemanni or Costa Rican Stripe Knee. I got her for my brother, but he's frightened of spiders, and isn't quite okay with her yet. Maybe when she gets larger. She just moulted, and burrows in dirt tunnels. You used to be able to see them, sort of like an ant farm.
Then, Hercules the
Heteroscodra maculata or Togo Starburst Baboon. He belongs to my boyfriend but I enjoy watching him. He's really skittish and doesn't come out of his burrows often, except to hang on the lid, waiting for his opportunity to escape.
