I have a feeling that it'll be Moyes, at the moment.
I still haven't voted yet, but I'm pretty sure Ancelotti would be the most exciting appointment. However, it would be wrong to be disappointed (although, with high hopes for Carlo, it'd be hard not to) if we were to appoint someone like Moyes or Hughes, who I think could do a good job. I don't particularly like Benítez (nor do I like Hughes) but I think he'd do well, too.
I think McClaren would be a big gamble. He did very well at Middlesbrough and Twente, but very poorly at Wolfsburg and as the England coach.
As for Martin Jol, I liked him at Tottenham and originally wanted him to replace O'Neill. However, he's been far from fantastic at Ajax and I'm not sure his relaxed approach regarding the fitness of the players would benefit us at all.