tell me about you're room and music tastes!!!
It helps to narrow things down a bit. If you're a hard rock fan, who likes to head bang, or Classical/instrumental/vocals buff, it makes a difference!..as well as whether your room is big, small, medium, etc.
I've sold the Krell integrated and Rega Planet over the years, and am very familiar. I've also sold/tried just about every conceivable kind/brand/model of speaker ever made as well! I've used/sold the following kinds of speakers on/with the Krell Integrated with various results: Thiel,Wilson,Maggies,Martin,Logan,Celestion,Kef,B&W,Vienna,Sonus F, However, my suggestions would depend greatly on the above mentioned variables in question.
I know the sound of the CD player and integrated very well. Tell me about what all you're dealing with, and perhaps I can be of some assistance. Thanks