Amsterdam or Oslo?

You can't go "wrong" with either one, as both have more than enough to keep you busy for a weekend. I'd say that as far as "sightseeing" goes, Amsterdam has a greater variety. Many of Oslo's sights relate to their maritime history (whether Vikings or the Kon Tiki). Both cities have WWII Resistance Museums, both interesting. Of course if you want to see Munch, then go to Oslo (I found the Munch Museum very interesting, particularly the pieces that weren't The Scream so I hadn't seen them before). And if you are drawn to Van Gogh or Rembrandt, then go to Amsterdam.

I too was concerned that so many came back from Amsterdam only talking about sex and drugs. However, I partook of neither of these myself, and didn't have any problem filling my days.

In your situation, I'd look at Rick's videos for both places, and see which one calls to you more. Here's Amsterdam from 2014: http://www.ricksteves.com/watch-read-listen/video/tv-show/season-8/amsterdam
and here's Oslo from 2010: http://www.ricksteves.com/watch-read-listen/video/tv-show/oslo

I'd also probably go with Oslo because it's easier to splice Amsterdam into a future trip, while Oslo is a geographic outlier. Also, Oslo's period of "good" weather is much shorter; if your visit coincides with it, take advantage.

However, while I wouldn't call Amsterdam "cheap," don't underestimate the expense of Oslo. It's certainly the only place in Europe where I actively sought out hotdogs from the 7-11 type places for dinner, just to save money. If you do go, consider the Oslo Card, which in 2003 cost me $50 for 3 days, but which I used for $75 worth of transit and attractions. If you can get Rick's Scandinavia or Norway books, they have very good money-saving tips for this very expensive place.

Having lived in Amsterdam and visited Oslo, I would vote for Amsterdam. It is more charming and interesting, has better food, and has a lot more to do. Just because a few of your friends want to do the same ridiculous experimentation the immature likes to partake of doesn't mean you have to. Don't spend much time with the druggies or the ones who want to visit hookers. Stay in another hotel. Invite the nondruggies to join you at different activities, sights, and restaurants. We never use drugs or get involved in nonsense and you don't have to either Plenty of people don't. Even if you are alone in Amsterdam, the people are friendly and welcoming and it is safe. You can join tours and meet others interested in the sights. You sound like you have a smart head on your shoulders.

I never say nice things about Amsterdam, it's not one of my favorite places - primarily because of the "smoking and experimentation" that, IMO, draw the worst tourist crowd. Drugs are hard to avoid and the city is dirty by northern European standards.

In this case, however, there is much more to see, and like, in Amsterdam than in Oslo. A-dam has good museums (I don't consider them the best in Europe), great architecture and interesting history.

Oslo has an out of the way, small-town feel. I loved Frogner park and liked the Viking Ship Museum (wasn't a huge fan of the Nobel museum). After that, Oslo runs out of things to see and do pretty quickly.

Oslo is also well out of the way, you will spend extra time and money getting to and from there while A-dam is convenient.

I'd go to Amsterdam. If you find you tire of it before you run out of time, spend a day traveling to another town in Netherlands. Netherlands is a beautiful country. Like everywhere else, big cities don't give you the best picture of a country or culture.

If you are a student then Amsterdam definitely gets my vote! It is a very "young" city with great nightlife and a lively social scene. I have several nieces and nephews who have done study abroad programs there within the last couple of years and they didn't want to leave!
That said, Oslo is also lovely and has great neighborhoods that cater to younger people - either way you really can't go wrong.

My vote would be for Amsterdam. No need to worry about the party scene. That's never been my thing but I do like Amsterdam and feel there is more to do there than in Oslo. Amsterdam has Anne Frank, fun canals to explore, great bike riding options, canal cruises, Rijksmuseum, Van Gogh museum to just name a few things. Oslo does have one of my favorite sculpture parks and has great Viking ship museums but then most of the beauty of Norway is out of the city. If you are comparing cities then go with Amsterdam. Comparing countryside then go with Norway.

Amsterdam is very cosmopolitan and hip. Lots of well dressed young people and intersting things to do. Count this fifty something and his wife as those that were happy to visit a coffee shop and see the red light district. Not like some on this forum who seem a bit prude. You dont have to partake if you dont want to but it's an interesting thing to see for yourself before you judge. Culturally, I was fascinated by the lack of police needed in the midst of what we Americans view as criminal activity. Those two aspects aside, Amsterdam is a cool place to visit.

It sounds like you want to have companionship on your "last fling" which makes a lot of sense. You say that a "few" of the group going to Amsterdam want to party. Sound out the others, you may find at least one or two who, like you, want to see the sights and stay away from the drugs. If not, then head for Oslo. Harold's described your options very well. To reiterate, it's easier to get to Amsterdam on future trips than to Oslo. In Oslo, you'll be with a good friend and a local to boot, so maybe he'll know some money-saving tricks.