I use QuickBooks.
It allows you to create sales receipts and invoices. It manages invoices for sales and purchasing.
With the invoices and receipts you can print and post of email.
I don’t think the SimpleStart version manages suppliers bills or uses sub categories.
The Pro version is a bit pricey, retails at £249+VAT but is available on Amazon for a total of £150 for 2010 version.
Been using quickbooks for the last 5 years..started with 2001 then 2004 now using 2006 windows 7 isnt that keen to run it for some unknown reason but then visat was the same and both of thewse are supposed to be compatable with vista and 7…my accountant gave me a license to use 2008 bit to complicated for me but 2006 regular edition does all i need from invoice quotes stock control and vat…plus dont take my paperwork to accountant just flash memory