The faster your site loads, the better. Impatience causes many people to surf away before a page can load. If your site takes more than 30 seconds to download over a 28.8 modem then you should pare down your site, because you will lose many potential viewers who will probably never come back to your site.

• In the first ten seconds, the page should have something for the viewer to see.
• A good target download time is 30 seconds or less for the whole page (including pictures).
• Site Optimization Tutorial from Webmonkey
• Total Page Size from Web Design Tips.
• So You Want a Thumbnail Image, Huh? from EarthWeb.