some countries require guest information - including passport number - at check in. whether its enforced is another matter. other places make you fill in check-in forms purely for market research. a place i worked at in melbourne made people fill in a check in form... of course we werent required to and then did naff all with the information gathered, so it was a massive waste of time. something i constantly mentioned to the GM. apparently we held the information incase the computers went down, and then we'd know who was in the hostel. that said, if the computers died we'd have been so far up sh*t creek that all the check in cards in the world wouldnt help.
CCTV is a great asset if the size of the hostels requires it - you'd be surprised how well you can keep an eye on a small place. but having it filming anywhere that money is kept, entrances and exits and the common room/bar is def. a good idea.
deposits are usually required because cutting keys is a pain in the arse and it discourages running off with them. personally im a big fan of them - from a management POV - because you can use that deposit money to ensure people check out on time (no check out = no deposit refund). the problem i have noticed with key deposits etc is that they can easily go wrong - in terms of accounting. id keep all deposit money separate from the rest of the till, to avoid confusion. a form of ID is also a great idea as it reduces the number of shifty characters you'll get (thieves are pretty loathe to hand over their details) but i wouldnt want to have 200 passports behind my reception in case something goes wrong.