Hosting from home really isn't a good idea. You will run into numerous problems.

If you are really serious about this, i would recommend you do the following things:

1. Upgrade your DSL to at least 8Mbps, if not replace it with T1 / T3
   
2. Think of investing in a small UPS so that you have clean power provided to the pc. (They usually retail here for about £30 - £40).
   
3. Get a PC which does not munch power otherwise you will see a 4 digit figure on your power bill!
   
4. Cooling - lots of fans or air con in the room you are going to house it in (its going to get very hot if left on 24/7.
   
5. OS - a stable platform like CentOS would probably do the trick. Install Apache, FTP, MySQL etc and your pretty much home and dry.

All in all it would probably be better paying a small amount a month for a professional company to host your site for you. They will do all the hard work and all you need to do is make sure your sites updated.