There’s an interesting story on Legal Week suggesting law students put intellectual stimulation over money in career choice. I am a bit sceptical.
I ask my students (if they want to be practising lawyers) something like this informally every year, but I also ask them why they think other students want to be lawyers. I get similar answers to the Legal Week survey but the students also think other students are much more motivated by the money than they are. Go figure. It may suggest a difference between stated and actual preferences or tell us something about how law students project their career choices to their fellow students outside the class room.
I think the interesting thing is then to probe them on their assumptions about where the most intellectually stimulating work is. These students have often done work placements, but their answers to the question how do you know which work is most stimulating are generally weak and unconvincing. They often have no real idea what the most stimulating work (to them) is or would be. They assume that the firms high up the league tables provide the most interesting work but cannot really explain why in a cogent fashion. And they know they have to pretend (and yep folks they generally are pretending) to find business fascinating and (with a certain amount of bemusement) to be commercially aware.
My (unresearched) conclusion is that in reality financial reward and weak assumptions about what will be interesting reinforce each other and that financial reward is what really drives initial career choices both for itself and as a proxy for ‘being the best’ (whatever that might mean in reality).
Lawyer Watch 
You are probably right about “intellectual interest” being a polite proxy for “show me the money”. It isn’t hard for an undergraduate who has had limited exposure to what legal practice is really like to make a stronger argument about why they want to do crime, family or even High Street practice generally – they are all areas of work which involve helping ordinary people with their everyday problems. It is difficult to make such a clear pitch for many areas of commercial/corporate practice as a student because even if you have studied them, you don’t really get to find out what working in them entails until you get into practice. There are some areas where the gap between the academic experience of studying them and practice are relatively small – eg my own main area of specialism of Competition Law and perhaps EU law more generally, so that if you find them intellectually interesting you will probably find them congenial practice areas to specialise in (and would struggle to work in them if you found them less than interesting).
Ironically, looking back on my career, the most intellectually interesting area of practice I’ve been in has probably been crime. While you need some street smarts and the ability to communicate with jurors, witnesses, clients and judges, what surprised me when I used to do criminal work was the amount of legal research and knowledge needed to be on top of procedure and evidence matters, as well as in sentencing. If you think a corporate partner does more intellectually complex legal work on a daily basis than making a submission on the hoof about the admissibility of similar fact or character evidence you’re probably mistaken! And if they do, they’ll have a cast of dozens to rely on in getting to the right decision rather than being a junior junior counsel whose client could spend a couple of years inside before it gets sorted!