The best system from who's perspective? The agent or Realtor attempting to attract leads or the consumer trying to find the perfect home on their own? As technology evolves, so does the need for agents to adapt their search tools to meet the consumers needs and preferences. Personally, I have been experimenting with a number of search features on my website (see link below) the newest of which has been the addition of link to Trulia. Also, towards the bottom of my main page, you'll see that I have added a city-specific box with direct links to listings in that area. Next, I plan to add mapping capabilities since (as Steve mentioned) most buyers want this feature. As an agent, if you haven't explored this link yet, check out http://widgets.trulia.com/.
You might pick up some new tools/features for your website. Best wishes with your website. - Ted Shoop