Cron,
It all depends what you want to accomplish, what hardware you want to target on the server side and also which browsers you want to target on the client side.
Also a big question is whether you want to hand write your website from scratch or are happy with generated content.
If you wish to connect to a database backend you will need to decide which one fairly early on as you will need to make sure your chosen language has the appropriate drivers for it.
One final consideration is once you have developed your website where are you going to host it ? - Last time I looked hosting on Windows based webservers was slightly more expensive due to the licennsing costs involved - so if this is actually going to be a 24/7 website make sure you check out the cost of hosting as part of making your decision.
For home based projects the open source options are usually preferred due to startup costs....
e.g.
WebServer: Apache
Pre-Processor: PHP
Database: MySQL
The above have versions for both Windows and Linux, so you can develop on your home machine and then host on a cheaper linux hosting platform.
Things to be weary about is that PHP has gone through itterations that are not backward compatible so there is no guarantee you wont be stuck with that as a platform should they alter sytnax again. PHP is based upon PERL so if you have any knowledge of this it may help.
In a commercial environment is use MS Internet Information Server (IIS) and ASP.Net, this is typically dictated to me by the fact that it is the clients preference as there is lots of development resource out there etc...
If you wish to look at IIS then you probably have it already, go to control panel/programs and settings or Add/Remove Programs and select the windows features option and turn on IIS.
You can then download free versions of Microsofts development tools e.g.
Visual Web Developer 2008 Express Edition and as a database you can get SQLServer Express Edition free.
These all have constraints but are a good way of playing about and learning.
It is worth noting you can get IIS to run PHP as a processor also, so you dont have to have apache and you can have PHP and ASP.Net exist side by side etc...
If you do use ASP.Net you will be restricted to the Windows Platform.
Without knowing what your trying to achieve its pretty hard to give some specific advice, but the above are some considerations.
Cheers