For small businesses looking for desktop accounting software
With AccountEdge, business owners can organize, process, and report on their financial information so they can focus on their business. Features include: accounting, integrated payroll, sales and purchases, contact management, inventory tracking, time billing, and more.
math lib for .NET. n-dim arrays, complex numbers, linear algebra, FFT, sorting, cells- and logical arrays as well as 3D plotting classes help developing algorithms on every platform supporting .NET. Sources from SVN, binaries: http://ilnumerics.net