That 5 meg speed is very slow and wouldn't supprt your having a very large number of visitors all at once.
Other issues include things such as if your server crashes in the middle of the night how long is it going to be before it comes up again (in a data centre the support staff would rectify the problem for you straight away).
It would be cheaper to arrange colocation of your server in an existing data centre than it would be to upgrade your connection to a decent speed and hire the necessary support staff to monitor your own server.
Of course if you are only expecting a few visitors and it doesn't matter if your site goes down then you can easily run the server for yourself. All you need to do is to install web server software such as Apache along with whatever other languages you require - for example to install Apache, PHP, and mySQL all in one go you simply need a product called LAMP (for Linux), MAMP (for Mac) or WAMP or XAMPP (for Windows).