tank size (and shape) depends on the type of spider
for your average terrestrial spider (ground dwelling), they will need no more than twice their legspan in tank hieght (this is because if they fall from any higher than this they are likely to burst their abdomen)
in terms of floor space, i give mine around 1ft x 2ft, for my bigger spiders, down to something about 5 inches cube for my spiderlings (they're about 2cm legspan max)
tarantulas really are slow creatures in their day to day life, tehy do not like to run around, infact most cannot run very fast at all.. they are on the other hand very jumpy, if they dont like something, most would sooner run away from it and hide (others will turn to face whatever it is; fangs drawn)
They are ambush predators, they sit and wait for their prey to come to them.. that said, soemtimes they do go looking, fi they know there's a cricket or locust or whatever in the area it really is interesting to watch them following the vibrations of an insect..
the cutest thing a tarantula does is clean, this is something you'd have to see to understand.
The most interesting thing (in my opinion) is when i spider molts, the first time you see one of your own spiders do it its comparable to something like a child losing its first tooth..
Things to look out for (more so than the fangs) are that a lot of tarantula species have uriticating hairs that REALLY (and i mean really) irritate the skin and eyes. they flick them at you in defense; this is opart of the reason i prefer my arboreal spiders.
some more pics of some of my collection at
http://pets.binary-pulse.co.uk
i love them, as does my gf, and i'm always wanting more.
EDIT: for a first spider, the general consensus these days is to get a Grammostola rosea (Chilean Rose or Chiliean Rose Hair), they are VERY hardy spiders, very hard to "accidentally" kill, have been known to last over a year without food, and are generally a very relaxed and handleable spider. - If you can i would suggest getting one off a fellow tarantula keeper than straight out of a pet shop - ones in pet shops are likely to have been wild caught and there's no telling what might come with it (for instance if its a female, it may already be gravid, which means shortly you will have about 100 of them).. there's various forums around, arachnoboards which has worldwide members, and the british tarantula society forums. both are good for getting spiders as well as very useful information once you've got one.
. I really don't like spiders although I do think, the big tarantulas are better than those horrible medium sized house spiders. Perhaps its because they're bigger and slower.
