Hiya,
well as they are Americans the first thing I thought of was that you should look at the Martha Stewart website (the Goddess of homely things), see what she's flogging and nick her ideas - she sells a lot of traditional European things so that
people can get a bit nostalgic.
http://www.marthastewart.comNow she is doing a lot of very nice glass blown tree baubles and you can get some beautiful ones here very cheaply, hand blown glass ones (or indeed the Swarovski Austrian crystal ones which are a yearly edition and 3 times the price in the US
http://www.swarovski.com/ go to the shop at
Marienplatz and they giftwrap for free) are a nice
gift and can become a future heirloom.
Steiff toys are always good but NOT cheap, of course if they collect Beanie Babies then please take a Germania with you, it is a small bear with a German flag on it which you can only buy in
Germany and gets traded for silly money on Ebay.
Schmidt is the best brand for Lebkuchen and they do tin collector's boxes so is a nice present (you could later reuse the box for cookies etc) and are widely available.
For small
presents (i.e. people you forgot about ha ha) I collect up Glühwein cups from the Christmas market (important that the city and year are on them), wash them and put a mini-Christmas market inside:
glühwein spices, a cinnamon stick, some marzipan, maybe a wooden decoration, lebkuchen or spektakulus and wrap the lot in cellophane - very cheap, looks impressive, light to pack.
As for beer/wine/spirits try something like Obstler (Enziangeist is an accquired taste) or go in Dallmayr/Käfer for ideas but a good Riesling goes down well with turkey and the trimmings (sharpness cuts the fat) and is becoming fashionable again.
Hope that this has helped a bit,
Katrina
PS for the baby shower I'd get the mother something instead as it always seems to me that she gets forgotten

Try Bio Basic (or other health food stores) and get things from brands like Dr Hauschka and Weleda as they are much much more expensive outside of Germany/Austria and many mum-to-be go a bit öko. At the last one I went to I bought Kneipp things especially foot products for the husband to rub in, pregnancy swells the legs and it is not nice she can still see her toes?