Robert_Charlton - 5:01 pm on Dec 12, 2011 (gmt 0)
If your business model is to track leads sent, you should track other channels of communication.
Are you tracking how many of your visitors navigate to other sites via your links to those sites? If not, perhaps you should if that information is important to you.
Similarly, do you include phone numbers? As I remember from various trade shows, there are systems that will allow you to set up tracking numbers, to let you follow leads sent that way.
Putting myself in the shoes of visitors to your site... for a great variety of reasons I would almost always prefer to use a direct link to the websites listed, or to make direct contact, rather than to fill out a form. Bad experience with forms over the years makes me dislike using them.
You might also want to consider how user-friendly your form is... whether, eg, it asks for too much information, and also whether it's compatible with auto-fill features available on some toolbars and browsers. All of this can be a factor.