Quickbooks, Peachtree, etc are accounting softwares. That'll get you a balance sheet and income statement. Wouldn't surprise me if a decent software has projection capability. Of course, there's always excel.
For taxes - I'm not familiar enough to know how far the accounting software goes into this. Realistically, you may end up using a separate tax software.
Given your long term intentions, it'll be easier and cleaner if you start at the beginning with a good accounting system that will grow with you. IE, start with basic Quickbooks, then add payroll when you need it.
For pros vs. cons of different software, I don't know enough to help, but I'm sure you can find plenty out there. Be careful not to cross into cheap territory. Hiring an accountant to unsnarl a mess is more expensive than to just do it right from the beginning.