So, Vault Dweller from the RPGCodex wrote a nice summary of quotes from the press and different game magazines. It`s for all those people, who can`t define the genre of Fallout 3. Some examples:
Actually it's interesting for me - it harkens back for me to some of
the most enjoyable first-person games I've ever played, the Terminator
games Bethesda made. Fallout 3 is Bethesda's triumphant return to
gunplay games, after swords and sorcery for so long. For me it's about
bringing back THAT legacy.
Emil Pagliarulo, Eurogamer
Fallout 3 is ultimately an action role-playing game. The game could be categorized as a first-person shooter.
You can read the whole thing here.