I do a business management degree at a good university, it is not a doss/poo/useless/waste of time of whatever you want to call it degree. In fact it is actually quite a good degree to do if you do it at the right university as it can be very well rounded and broad, giving you plenty of options afterwards. However, I will happily admit, that if finance and investment is what you want to do, then economics or maths may look more favourable. That doesn't mean you have to do that though, and in fact, there is no point doing them just because you think you should. It is better to do a degree that you feel happier and more comfortable about as you will do better in it. What's the point in struggling with a degree that you don't like, its better to have a 1st or 2:1 in something like business managment than a 2:2 or third in economics.
Also, it is not just the degree that matters!! On BBC news the other week I heard that there 70 graduates to every place, which is a lot. Whilst some degree's may seem better to do, doesn't mean you will get the job. With so many people with degree's out there you have to differentiate yourself, show initiative and enthusiam for your career. Placement's will be the key. Get a good relevant placement and you are on to a winner. Not only will this differentiate you from the rest of the pack, it will also give you knowledge and experience, and this is what companies like most. At the end of the day, whilst a degree is good, it's sad to say that they just don't carry the same clout as they used to, if anything, they are now seen as a minimum requirement for many jobs. Also, as well a internships/placements, look at investment qualifications etc. If you want to go into this area you will most likely need to have some qualifications, and whilst most companies will help you with them, it looks better to already have them, or some of them before you graduate.
Do what you think is right for you, not what you think you ought to do. Also, think outside your degree. I speak from experience, choosing the wrong degree at the wrong place, leaving before I finished my first year, and wasting that year. I then chose something I wanted to do, and am now much happier and doing much better.
Hope this helps,
Tom