http://www.eleven2.com/hosting/
Used them for the last 12 months, been alright so far and got a good deal at the time for the annual signup. They have a new years offering by using coupon code "newyear". By the way, I am not saying this is the only offering out there, there are literally thousands as you may have already seen!
As others have said getting a "business" line at home still probably wont get the sort of service you will need. Even shared services with a host provider is better suited I feel.
The logistics of backups can be a problem as well, if you start hosting databases and the likes on your webserver.
Even if you decided to pay a company for your own dedicated box hosted in a data centre this would probably be more suited.
Anyway, when you weigh all the options up: expected user traffic, cost, uptime, backups and continuity plans you will have your answer.