I happen to be fortunate enough to have hi-speed internet at work and DSL at home. Worst-case scenario, I have 640Kb/s downstream and I still prefer sites optimized for dial-up. Why? Because with few exceptions, most of the broadband-optimized sites I encounter routinely fail to utilize the extra bandwidth with worthwhile content. Instead I usually get 28.8 Kb/s worth of content, and 600+ Kb/s worth of filler.
Do your clients a favor and optimize the sites you build around the content they need to deliver. Anything above and beyond that is wasted bandwidth. For me, a "richer web experience" can be found on sites with good content that is easy to find. Flash intros, animated menus and large graphics are not part of that richer web experience.