Real live foreigner stepping up to the plate 
I have been living in Sweden for about 8 years now, give or take.
Language: You will get by in 99% of cases with english. In fact you may have a hard time learning the language due to people wanting to speak english with you instead of danish/swedish. Native english speakers tend to have pretty bad swedish in my experience. Since locations are off, I can’t tell if that is relevant for you. Both languages are easy enough to learn, but for my money Swedish is the easier to pronounce (biased I admit).
Kids: Most larger cities in Sweden have international/english-speaking schools if you don’t intend to live here permenantly. There may also be bi-lingual schools in Gothenburg. If nothing else, it is very likely their teacher will be able to communicate with them in english while they pick up Swedish at day-care. Here is a link to one of the english-speaking schools in Gbg, they should be able to tell you more http://www.abcallaboutchildren.com/aboutus.html
People vibe: People think that the swedes are cold/reserved, but that it isn’t really about that. The swedes just have a very high “personal space” threshold. This means that the reason they don’t talk to you is so as not to disturb you. If however you start babbling at them at the busstop (I am Irish) then they usually respond enthusiastically. To overgeneralise a little more, they have a clear boundry between friend and stranger. For friends you will do anything, but strangers can look after themselves. These two things lead to the swedes coming of as rude and standoffish until you get to know them, one at a time 
System vibe: I usually describe this in terms of frames. If each culture has a frame, then they are all made of different materials and are differently flexible. In sweden they are made of titanium
100% is the order of the day. You will very, very rarely get less than you are entitled to or would expect (be it help, service, quality, etc), but you will very, very rarely get more. This is for good and for bad, same as anywhere else. At home the frames are much more flexible, so you will often get astounding help, or service or rules bent or whatever, but just as often you will be left up shit creek cos you only got 80%. An example is that in Ireland I was allowed once to cash a check that I should by rights have been forced to deposit. They let me cos I had a good reason and asked nicely. There is no way in hell that that would have happened in Sweden. Just plain isn’t going to happen. Ever. It is this rigidity that means that my pay is in said bank on the exact same day every month so that I never have to worry about my pay being late to pay my bills. Busses in Ireland will wait for you if they see you come running and waving, but on the other hand busses in Sweden come at exactly the time they are supposed to, because they don’t wait for people. I guess it boils down to that the difference is between in Ireland having moments of perfect bliss in a general sea of unsurity, you get instead in Sweden big rocks of irritation on a meadow of general efficiancy :eek:
Ok, this nicotine chewing gum is starting to really kick in I notice. I better stop typing now.