Is a web site worth the investment?

This question is really aimed at smaller practices, and I'm really asking for guidance from actual experience (I'm sure I know the opinions of designers of web site for accountants......)

We are a relatively small bookkeeping & accounting business ready to hatch ambitious growth plans.

Over the past 4 years all our business has come from low budget advertising in local newspapers, and recommendations.

But we're on a mission to take on more business (maybe the world), and we've invested in a display advert in the forthcoming Yellow Pages.

Now, the question of whether a web site would be an effective marketing tool to generate new business has become a hot topic (especially since our local Business Link has matched funds available to help businesses gain an interet presence). We have divided views (dangerous in a small practice where marital relationships as well as business needs have to be considered).

Will it be an effective way of winning new business? Or are there more effective ways we could use the budget?

And if having a website is a "Good Thing", is it better to keep to a simple brochure format, or add in Clever Things that web designers tell you will make money (erhem!).

The boss (with the purse strings isn't convinced). The Universal Canine Cadaver (ie General DogsBody) with the maarketing hat on this week thinks it's a dead cert (providing we use all the right words to raise our position in searches).

Opinions please......
Peter Wood