You can get into a lot of jobs with a maths degree as long as you display enthusiasm and knowledge of the field you're going into. A lot of my maths friends went into investment banks, financial consultancy etc. A more maths-intensive financial job would be to work with an Actuarial firm. Accounting is another option but you don't really need advanced maths for this.
The type of degree is not that important unless you are going into a field where you are likely to use it. So for an investment bank, it would be helpful to do finance options (derivatives, options etc). Otherwise they are not too fussy about the degree specifics (a lot of what you do at uni won't be required in your job anyway).