Presents for the Host

This has probably been discussed somewhere already, but I haven't been able to locate a thread on which presents to give to your host or business partners. I hope that everyone with experience or knowledge can chime in in this matter. I've read some general advice like "something typical of your home country", but I don't the stuff you get at tourist shops (little copper Eiffel towers, Big Ben candy boxes, wooden figurines for burning incense cones, small cuckoo clocks, a chocolate Miss Liberty,... you get the idea) will elicit a lot of enthusiasm. What makes it even hard is the fact that you normally don't know much about your hosts (at least not in advance), so I'm unsure what to get before travelling.

What gifts are suitable for (female/male)

- business partners

- tutors at the uni /helpful acquaintances

- people in general who invite you to their homes

- roomates (if that won't come across as awkward)?