Personally I would recommend www.xero.com or if this doesn't take your fancy check out one of the many other online bookkeeping packages. Plenty of plugins, excellent support and more features now regularly added.

Whatever you do decide please stay away from Sage!!

If you are a services based business, I would also look into the upstart freshbooks.com, they are quickly becoming integrated in most of the 3rd party tools for startups. Sadly though, yes, Quickbooks is the defacto standard and most widely available for integration with 3rd party tools, which is very important, when trying to integrate with say an e-commerce site or payment processor.