A quick look through the names being bandied about:
Hiddink - He's a free agent, so if he was brought in to steady the ship as we shopped for a replacement he'd be a very good choice - although we would need to get a bloody good manager next summer, rather than start from scratch again
De Boer - Doing a good job at Ajax, and is familiar with Verts and Eriksen...although success in Holland with Ajax isn't that difficult
Capello - His wage demands would be excessive, plus he isn't that popular, even in Italy he gets grudging respect rather than being lauded. Also, he has history with Factitious Madrid, which counts against him after the last couple of summers
Benitez - Only just took over at Napoli, so activating his release clause would cost a bomb
Laudrup - Flavour of the month, and his summer transfers have indicated he isn't a good operator in the transfer market (notably with Bony and Shelvey)
Pochettino - On the one hand he seems to be flavour of the month, but he has Southampton playing like we want to play, and is a canny operator (i.e. Ramirez, Lovren)
Clarke - Yet another flavour of the month. He's got West Brom playing above themselves, but there's a step up between (and I mean this with the utmost respect for Clarke, and with none intended to West Brom) managing West Brom and managing Spurs, which could count against him
'Arry - Ignoring the usual "you should never go back" comments from pundits far and wide, he'd be a short-term solution (which he was supposed to be in the first place), and has proven that he cannot work with a large squad - and that's before Spursguru and PNP hitting the nail on the head in terms of his squad management