which linux distro
choosing a distro may be a prob i admit , but it actually depends on what ur application area revolves upon , debian is considered a very good dist bcos it is highly stable and still quite tough to handle , install and configure , on the other hand if it is just a desktop pc you may go for SUSE bcos it is extremely user friendly , I have used RH all my years , i suggest that , still today RH 7.1 I didnt have to change it bcos it still suits my needs , but i definitely agree with the other fellows here , its really upto you to decide .. But for ur question i assume u really want to go for experiencing a deeper depth of the linux kernel area .. I suggest go for DEBIAN .. it will help ..
Thanks and all the best ..