I'm doing International Studies and German at Monash. Ninwa has already said a lot but I'll put in my opinion. German at Monash is great and I agree with what Ninwa has said about the tutors, however - the 'Culture' component is absolutely terrible. You will want to bang your head against a brick wall after every 2 hour session (unless you're a huge fan of philosophy and you enjoy debating about NOTHING for several hours).
I don't think it really matters too much about whether Monash is 'ugly' or not. I know it is compared to UoM, but once you're there you won't really care. It's especially bad in the Winter months because it feels even more drab, but I think some parts of Monash can look quite pretty. Especially when the sun is out - lots of green grass and trees. Even the fail-pond isn't looking too bad this year, haha.
Atmosphere is really good if you get involved. That's really up to you. If you do a language you're pretty much guaranteed to make friends in your tutorial because it's really interactive. In other classes where it's based around discussions on the content, less so, unless you go out of your way.
If you're interested in International Relations maybe have a look at the different first year subjects and later year electives you can take and see which ones from UoM/Monash appeal more to your interests. The first level sequence for International Studies is quite good in my opinion - in first semester it covers history from 1945 onwards, and the second semester focuses on globalization. This depends on your interests though, I know ninwa has said she hated Contemporary Worlds when she did it. If you're interested in International Studies Monash also has Bachelor of Arts (Global) which is pretty much majoring in International Studies and spending a semester overseas as part of the degree. It has two 'global' units which focus on global studies (I haven't done them yet but one looks fun haha - you get to write a blog and have email discussions with a student from a partner university). You can pretty much accomplish the same thing doing just straight Arts (except for the global units), but hey it sounds a little bit fancier when you tell people what you're doing
I can't say much about geography though, have a look at the related subjects for both unis
That being said, doing breadth subjects from the Environments faculty at UoM could be really helpful if you want to major in geography. I've got a friend interested in Geography who has spoken really highly about a lot of the environment subjects.