XHTML with jQuery means better SEO
Years of research have demonstrated that cleaner XHTML code helps search engines find the content you want them to find. Search Engines look at hundreds of factors for your pages, using jQuery you can load in content that is less relative to search engines thereby increasing your page keyword density.
Do smart SEO, establish your keyword goals early on and integrate them into your verbiage for your website. Don't let your content dictate your keywords, picking your keywords first can help you flush out a direction to go for your site. Clear communication with your Web/Print Designer about your marketing goals can only help the overall process.
Want to know more about what Google considers as factors for how it ranks your site?
Check out this article explaining 100+ Google focus points.
jQuery and Twitter
Are you into the Social Media craze and use Twitter to help promote your business? I've written plug-ins to show recent tweets right in a client's blog, just a simple way to get more of your content in front of your customers. Tools like this can be placed into HTML pages to help keep your content fresher more easily, helping to increase your SEO Ranking from sites like Google.
Customer Centric Sites
A web page should be designed to get your point across and should be a good tool for your customers. Take time to look at your website from your customers point of view, are you providing what your customers need to know to choose you as their supplier? Provide fresh content and good information to tell people who you are and help them buy from you. Remember that content is king and a website is a cheap way to get your message out, use it wisely. Don't forget to tie your other marketing in with your website, if you have a Radio, television or even bus ad, your webpage should be listed with it.