Reach your audience...
I construct sites for everyone to see! Many websites are written with scant regard for the variety of web browsers currently used, for people on slow internet connections, for the variety of monitor sizes now available or for the variation in sightedness in the population.
Aside from the denial of information to large parts of the population this is not a good business model. Instead, I use modern techniques and 'web standards', ensuring compatibility with the latest and, just as importantly, future web browsers. This ensures the client will reach more of their potential customers.
Accessible to all...
Partially sighted users should be able to adjust the text size easily. Colours should be chosen for clarity and be suitable for colour blind users. Content will be written with consideration of screen readers for the visually-impaired. As screen readers are like search engines in that they like textual content (as opposed to features such as Flash) this also means that your site will be regarded well by search engines such as Google - and how well Google indexes your site will influence the number of visitors you have.
Bells and whistles...
Many browsers have 'extra' bells and whistles - which when used appropriately can be a good thing. I will however ensure that user's with older or simpler browsers can still access your site. Similarly, screen readers for the visually impaired and search engines will still be able to read your content.
Maintainable by you...
Clients should not have to pay a web developer by the hour to update their site just because a few words need to change. I build sites using a Content Management System so that sites can be updated easily and without technical know-how.