IMHO MYOB is perfect for the small business (because it's designed for them).
I've used it myself, in the past, when working for a couple of small charities and it's all you'll need.
It includes sales and purchase ledgers, credit control (including built-in letters to chase defaulters).
There's also an excellent stock control module and it will also calculate your quarterly VAT return!
They also have an excellent telephone support service which, I seem to recall, is free for the first 12 months.