There are many to choose from, and most of them do at least an adequate job. I have worked with Peachtree and with Quickbooks, and prefer Quickbooks. It is easy to learn, it can grow with your business, and has both Macintosh and Windows versions. They are stable, and will surely be around a long time.
Quickbooks is a very inexpensive but effective solution to manage your business checking account. Not only can you keep track of your expenses but you can also do payroll and write checks from it too.