Hi Jorge It's great that you are learning Drupal, Welcome. Do not worry about the messages that say some modules are now in core. If you knew earlier versions it may be of interest but starting with Drupal 7 it does not matter.
Drupal 7 has many modules but is waiting for some of the more popular modules to be converted from Drupal 6, it's very functional but not complete. I leave it to others to discus relevant modules and memory.
I'm building a site with 32 pages of Cyrillic text and images but there will be no visitor input. It's using Marinelli with the borders and header switched off and the background a light blue/grey I chose this because it has the menus on the right. For me menus are of low importance in this instance.
As for themes maybe you can start with Garland or Bartik,you can chage the colours or remove them, later you can move to another theme. I do all my building on Bartik for D7 then change to another theme if I need a different look and feel.
Stark 7.0 is a clean no frills theme. Good luck Roger