The ones with valuable content, properly SEO'd, and kept fresh.  

Well the only website you have complete control over is your own.

W/ fresh content, SEO, and all that jazz you can make the biggest gains because organic traffic comes free and can be scaled without the need to pay per click or thousand impressions.

I actually just posted my first AR blog on this very topic last night. You can read the RE blogging framework here.

At the end of the day, I think consistency is going to be your biggest ally!

Your own website with great call to action ads and landing pages. See our own experts here:

There is no way to quantify or document this.

Carol Williams nailed this one!

It depends on who you talk too.

The Evll Empire has one suggestion and BoomTown another.

And, as others have noted, this question is a bit COSMIC, meaning it is to 'undefined' to result in a meaningful response.

Everyone would agree the leads of greatest quality are those that are the result of stimulating passion. It is hard to stimulate passion in a vast sea of sameness.

To be valued by consumers , a website must have new content on a daily basis !

I think Annette Lawrence , Palm Harbor, FL 727-420-4041 has made a valid point -

100+ different answers. Which agents create the most quality leads? No way of knowing,

Mine creates very good ones.

My website ALLATLANTACONDOS.COM 

The website that you have developed and finely tuned.

Carol Williams said it perfectly, and I would add that you need a beautiful site that does not look like everyone else's and is not cluttered with info.

Mine.

Your own. If you don't have one - build one. Start now.

I am here for the same answers and think I got it!

The one that obeys the law of attraction. Specific people looking for specific skills that are targeted by you.

Jeff Pearl nailed this one!

Our webside.

You can make website that will work, or you can buy leads form huge sites like Z., Realtor, etc. There is no other way. 

There is no one answer that covers that for different agents

My own

  Carol Williams has this one.

Great question!

For my purposes in marketing my listings, the best sites that generate leads for me are Listings2Leads and Realbird.

For general leads, my websites leads are the best!

my personal website.... listing leads.... I use that url on my postcards...those who do not want to call, leave an email message via my website....

I just keep working on my own website, always trying to learn more and stepping it up.

No such things as any website producing the "most quality leads".  None that can be purchased anyway.  I am a firm believer in organic and owing with full control over my own site. 

Good luck.

I wish we knew.

Donald Kolenda Your own website.

The best quality lead are those which you generate yourself. Leads from blogs, leads from current listings, leads from sales, leads by word of mouth. There is no magic website for leads

We use only our website for our leads.

The one with good information that consumers like/value.

Do you mean what type of website as in a Wordpress or something else?

Or are you asking about other sites that sell Leads or views?

 The one you put content on constantly and have interaction.

I'm not sure.  I think leads can come in a variety of ways.  Sometimes it's not the lead but the conversion that produces the quality.

My own with lots of local data and neighborhood info and tons of links.