Valencia centre-back Carlos Marchena was included despite a mediocre season, while Morientes was ignored after failing to find his scoring form at Liverpool.
Morientes has found the net just nine times for Liverpool this season, but has an impressive record when he has played for Spain, scoring 26 times in 43 games.
The former Real Madrid striker went to both Euro 2004 and the last World Cup, but missed out on Euro 2000, an omission that then-coach Jose Antonio Camacho later admitted was a mistake.
Valencia striker David Villa, who has scored 24 Primera Liga goal this season, is now the favourite to lead the line with support from either Raul or Atletico Madrid's Fernando Torres.
"I've given priority to the players who suit the way we play. We can't put the interests of individual players before those of the team and its stability," a tense Aragones told a news conference.
"I'm not taking Marchena just because he helped us before. It is a question of taste and I like him as a player."
Marchena's Valencia team mates Ruben Baraja and Vicente were left out, as were defenders Joan Capdevila and Javi Venta who had both been invited to last week's World Cup get-together.
Baraja was a regular in the team during Spain's qualifying campaign, but Vicente has been struggling with ankle problems throughout the season and has only recently recovered full fitness.
"I've had to think about it very carefully but I haven't lost any sleep over it," said Aragones. "It isn't always a case of just taking the 11 best players."
KNEE INJURIES
Raul and Barcelona midfielder Xavi were both included despite missing much of the season with serious knee ligament injuries.
"I believe in Raul completely and I think he will have a good World Cup," said Aragones.
The Real Madrid striker has not scored since returning to action in the middle of February.
In midfield, Villarreal's Marcos Senna has been included at the expense of Baraja, while Barcelona youngster Andres Iniesta, who has excelled during Xavi's absence, also earned himself a place in the squad.
Arsenal's Jose Antonio Reyes is the only naturally left-sided player among the midfielders, although both Luis Garcia and Raul can also play there.
"Spain has some very skilful players," Aragones told Spanish television channel La Sexta.
"We have an extraordinary group of players whose average is age is around 24 which has to be the youngest in the World Cup and for me they are the best 23 players in the world."
Spain have been drawn against Ukraine, Tunisia and Saudi Arabia in Group H, playing their opening match against the Ukrainians in Leipzig on June 14.
They will play three warm-up matches, starting against Russia in Albacete on May 27.
They meet African champions Egypt in Elche on June 3 and fellow World Cup qualifiers Croatia in Geneva on June 7.
Squad:
Goalkeepers: Iker Casillas (Real Madrid), Pepe Reina (Liverpool), Santiago Canizares (Valencia)
Defenders: Antonio Lopez (Atletico Madrid), Pablo Ibanez (Atletico Madrid), Carles Puyol (Barcelona), Juanito (Real Betis), Asier del Horno (Chelsea), Michel Salgado (Real Madrid), Sergio Ramos (Real Madrid), Carlos Marchena (Valencia)
Midfielders: Cesc Fabregas (Arsenal), Jose Antonio Reyes (Arsenal), Andres Iniesta (Barcelona), Xavi (Barcelona), Joaquin (Real Betis), Luis Garcia (Liverpool), Xabi Alonso (Liverpool), David Albelda (Valencia), Marcos Senna (Villarreal)
Forwards: Fernando Torres (Atletico Madrid), Raul (Real Madrid), David Villa (Valencia)
