Server 2k8 with IIS, SMTP and FTP
Windows 2008 comes with IIS 7 which is a pretty powerful if somewhat complex in my experience.
For FTP service you'll want to download the update from MS if you're not on R2 or better, but for the rest of us, you need to know that you'll need to enable the IIS Manager for 7 even if you had the manager for 6 automatically installed for other purposes.
In my case, I added IIS for the feature of making it an SMTP relay host for itself using it as a smarthost to point to our regular SMTP server. I needed to do that so that I could take advantage of the File Server reporting that it comes with. You should note that SMTP relay is dangerous so I recommend limiting access to 127.0.0.1 (the local computer) unless you are specifically intending to allow other uses and if you are, then to restrict it and read up on SMTP Relay carefully.
Once I had SMTP, I also got IIS and FTP with it, but I couldn't manage FTP with the manager it installed. For that I had to add a different feature, the IIS7 manager separately. With that I was able to create a new site and set up the user/authentication/path that I needed for that separately.
I also had some trouble getting our Data Protection Manager server to recognize the system, so I had to install the agent manually and then attach it manually at the DPM server shell. It is obvious and well documented by MS if you know that is what you need to do, but learning that part took me a while.
Other Services you might appreciate from Server 2k8
Windows 2008 also comes with HyperV which is one of the better free virtual hosting systems available.
The Active Directory tools built into 2008 are easier to use than 2003 and adding it to your domain is really easy so I can highly recommend it
DHCP and DNS were also added in the process, but a word of warning: DHCP migration with netsh wasn't bad, but I had to specify the scope specifically that I wanted and the router setting was not migrated so machines started popping up without a gateway set. If you know to look for it, it won't be a problem.