Were using Suse 9.0 Pro on our web/email/dev server. From my experience, Linux is linux no matter what distro you use. You can go as far under the hood as you want, though each has their little tweaks. Suses contribution is the Yast wich gives you the opportunity to take care of a lot of maintenance issues (patches, user scripts, firewall, etc) through a GUI. You can still use the command line if you want, its not like they took it away. For a noob, its good, but if you want to learn through force, one of the other distros may be the way to go.
One really cool thing is all the open source software. Right now we run our CM through CVS on the linux server. We use tortoise to interface with CVS -- it integrates seamlessly with windows explorer. Plus, if you use Ximian, a graphical environment based on gnome, you can get the benefits of .Net emulation on you Linux box through Mono. Were in the process now of setting up "test on commit" scripts to run unit testing on the linux box after every commit of the .Net apps we developed in Visual Studio on our windows PCs.
The best part -- All the above mentioned software is available through the open source community. Which is where the "dont get hacked" comment came from. Becuase everything is open source everyone can see the code thus exposing vulnerabilites to that code making things easily hackable. The good thing -- everyone can see the code so things that are hackable are found and fixed quickly. Many eyes make safe software.
Sorry, you guys hit a subject Im very excited about. Good luck with your linux experience. Ive had nothing but good times with mine...after overcoming a small learning curve. I mentioned a lot of different stuff above...all of it can be found on the web pretty easily. Thats how I found all of it. Good luck and have fun!
. Ive also set up openSSH and Putty on my comp so i can set it up remotely .. useful if you wanna browse the net and do linux stuff (e.g. view a tutorial on the web without using KDE, but using windows and putty to connect).