I'm not 100% sure how things work in the states, but in my country your leased line goes through a first/second-tier ISP. Usually they can provide you with web/mail hosting on their external bandwidth.
Eg:
512kbit line between ISP and client's office.
The client's exchange mail server is hosted at the ISP.
The ISP's backbone has +/- 40mbit peers and therefore mail is delivered to the server at "optimum" speed.
Between you and the server, you recieve just about your full 512kbit, because the mail server is only a few hops away from your leased line (as opposed to a large number of hops to a "off-site" host).
Although this example uses mail as a medium, you can just as easily ask your provider to host a web-server for you.
This way, you will get 512kb download speeds between your office and the server and browsers from another country will still get good speeds because of the ISP's peering.
The best of both worlds...