It is worth mentionting that with the advent of tabbed browsers it’s now so easy to multiple sites open automatically as your home page, thus in some user cases voiding the need for SpeedDial and/or a single aggregator page. For eg, I have Facebook, Brizzly, Gmail, Greader & BBC pages all open as seperate home pages as I use them all frequently. If you have all those pages open in separate tabs that you want to set as your “home” pages Firefox allows you to “Use Current Pages” under Tools >Options > General (the quickest method!).
P.S. I don’t know about Safari, Opera, et al, but certainly for Firefox and IE the blank start page url is “about:blank” – not “about:home”.