Sounds like Martinez to me!
This is always the best thing to do, but its like the club (and so many others) have a gambling problem. The 'best man for the job, or the best we can get' is always appointed, but when things go wrong the grass always becomes greener, and there's absolutely no doubt in my mind that if we appointed someone else they'd be under the exact same scrutiny Pardew is now, even if they have a better philosophy. If he didn't have the relationship he has with the hierarchy he'd be out already, I wasn't a fan when he was appointed, won me over last season (yes like pretty much everyone) but those initial fears seem to have been realised.
It's either an endemic problem, or just the nature of management. It's easy to look at the Ferguson's and Wenger's as the ideal, but in reality I think they are more the exception - and not an exception that can be easily predicted upon appointing a manager.
I'd give Pardew another 6 matches to turn it around, if we're still spiraling out of control Ashley really should make a move. Saying that, if the ship goes down, I think the captain will be coming along for the ride.