Amp: Integrated - Used; - Sub $750 Help :-

Hi All --
Been reading through all the threads and every situation is so specific I figured I'd post up and see what people think :-)

I have:
B&W 601 on stands
just bought - Rotel 1072 CD
running through old Marantz 2220B

I would like to upgrade the amp - it is a bit muddy and I think the speakers/CD can sound better based upon the 685's I have in my main A/V system (integra 7.8)

I have been looking and am getting confused and don't want to turn this into an epic buy and replace search.

I listen to a wide variety of music so I need something versatile. I really like 3d soundspace (as I'm sure everyone here does!)

There is the NAD C352 - but I don't like the cheap feel to it.

There is the Arcam Diva A75 - but I read that it is boring and that scares me.

There is the Rotel - I have a line on a RX-1052 for $500 - which is a receiver but I'm sure sounds good - leaning towards this?

There is the cambridge - 540v2 and the 640 - which seems to be liked ...

So -- I would appreciate input / help. I don't mind waiting a bit to find the right amp - but I am pretty excited to get things in good working order! (I'd like to pry the 685's off the movie system - but my wife wouldn't be too happy - and she's green lighting this! one step at a time!)

thanks a bunch
Ethan