I myself don't build websites often (I'm crap lol) but I thought coffeecup was pretty good. Don't know if you've heard of it but it's meant to be one of the best. I liked it.
Coffee Cup I thought was only an html editor.
My aunt has all their software...
FTP, Flash, and more stuff..
I havent come across any online website builders yet...
OFF TOPIC: Hey gooooogle, I clicked on your sig, and checked out your site.
Your little banner with the gold painted server cases are pretty cool.
i use the same cases for my primary computers, except they are black.
Antec makes good stuff
Look at SiteSuidio at http://psoft.net. Still looks like the most economical way to provide an online builder. There is also trellix but pricing is high enough to keep all but the largest host away. You could also look at http://builtsmarter.com. They are still working on pricing.
I think the best site builder in town including with awesome web templates designed would be Site2You which is a sister company of Template Monster. You could check it out at www.Site2You.com