invoiceit!

From The Scrambled Card Company:

invoiceit! - the all-in-one business software solution. Whether you sell products or time-based services, invoiceit! is an all-in-one professional accounting and invoicing solution with more features for your money. Features include cashbook finances, invoicing, quotations, automatic invoicing for regular sales, inventory/stock control, client and vendor tracker, reports, illustrated price, multi-person diary, email, integrated direct mail module (for example: write to clients who have bought certain products in the past) and highly customizable stationery - your invoices look exactly as you want them to. Payment receipts are automatically cross-posted to accounts.