Hello everybody,
just want to share that after the failure of my macbook pro at the beginning of this week, I took it to a apple center, and they confirmed my (our... friends of the forum helped!

) diagnosis: graphic card was the issue.
So, in just 2 days they replaced the entire logic board under the extra-year warranty apple granted to early santa rosa macbookpros, and I'm picking it up tomorrow morning!
So far, so good!
Thanks all for the help,
Lory