Welcome to the forums Gustavos.
It would actually all depend on what features you want and how much you are willing to spend...also on what you will use it for..e.g. hobby, sports, professional work..etc.
Depends on your needs. The main advantages of the Pentax system for me is that you can buy good used lenses back from the 70s for a bargain and they will fit to your camera, and also because they offer top notch gear with weather sealing (K-7, K-5 and lenses) for a reasonable price.
If you can find a shop offering Pentax in Colombia you may want to get a K-x or K-r, those certainly fulfill your student needs. Then, you can always hunt for lenses on online sites or thrift shops, I do this here in Brazil and always find some gems.
If you need to ship the camera though, you have to study if it will payoff. It might be better look for an entry-level Canon or Nikon, to which you may find more lenses and accessories available on your area.
Last edited by hcarvalhoalves; 05-30-2011 at 10:52 PM.