This is also for the web designers, not only for photographers. It is always good to make a point fast and then let the visitor make a decision the World is moving fast and we donandt have time to view all the crap work people have done. Therefore only show the top notch work and let the potential client move on, if he wants to. Donandt keep him tight he will leave without seeing every piece of your work anyway.
Is is also a good idea to order your pictures. Even if you select your best work, some of your pictures simply have to stand out. Put them first and leave the other good ones for the second page.