What small businesses really care about is cost effective customer acquisition.
A new website without a marketing engine attached is a tougher sell and is a crowded marketplace - you'll wind up selling against Intuit, Yahoo and other giants that have a virtually unlimited inbound flow of leads (small biz that buys QuickBooks etc).
SEO is effective, but slow.
Google's new hyper-local search features are perhaps a faster payoff for SEO but there are plenty of localized SEO / SEM companies already out pushing that pitch like Real Local.
All that naysaying notwithstanding, there's a great opportunity to build something incredible in the small business space but it's not unconquered from lack of trying.