When presenting your business plan to an angel investor you must understand that they will be very interested in your spreadsheets and proformas, but you must also realize that it is typically an entrepreneurial optimistic approach, which causes problems with proformas. Therefore, you should have dueling spreadsheets; that is to say the spreadsheets, which take your best guess and double the time, double the expenses to compete with your optimistic approach. You should be able to present both of these to your Angel Investor; who chances are is a retired business person with a little bit of financial savvy.
Just as with HTML editors, various open-source software programs have sprung up to provide an alternative to the dominant player, Dreamweaver in the case of website editors and Microsoft office in the case of office application suites. Whereas in the webpage authoring arena you have NVU, SeaMonkey and KompoZer, in the office application suite you have LibreOffice (formerly called OpenOffice) and NeoOffice.