[Oliver_Kahn]

From those you've mentioned, I'd say Valverde and Blanc have no chance. For different reasons, the first is Espanyol's manager, Espanyol are one of Barça biggest rivals, getting Espanyol's coach would be humiliating themselves. Blanc has no experience to lead a team like Barcelona.

I don't think Mourinho would like to return to Barcelona, I'm sure everyone remembers how he was treated the last time Chelsea faced Barcelona. The chants were like: "Fuck that Portuguese bastard" (in Spanish obviously).

Laudrup is a risk I'd say, he has never coached a top team like Barcelona, so you just never know whether he will be successful. Coaching a smaller team is usually easier, a lot less pressure on his shoulders and no supporters questioning his every move.

Guardiola is my dark horse, honestly I think he has a shot at coaching Barça. From what I've heard, he is doing a top drawer job with Barcelona's B team, he is a Barcelona legend, a fan favourite and a former captain. The only problem is whether he is ready for the job, because coaching FC Ego's ain't easy and he hasn't yet be tested against strong opposition and more experienced managers.

Marcello Lippi will have offers from Italy probably, so I think he'll rather take those. Clubs such as AC Milan or Juventus are IMO more appealing for an Italian coach than Barcelona.

Manuel Pellegrini would be a great choice, he would be my first choice if I was Joan Laporta.

Rafa Benitez is indeed, like Patricia said, Laporta's number one choice and I'd say he would be interested in returning to Spain. But it all depends whether he can win the CL with Liverpool. If he wins it, I think he'll stay. If he doesn't he will most definitely consider taking over at Barcelona.
Rafa Benitez