This system sounds great for the money spent, but is a definite upgrade candidate. My fantasy is to replace the NAD with a good tube front end, like Manley, e.g. The speaks still rock but are also upgrade candidates. The LP12 is strong but showing its age. The cdp is updated but not nearly as sonically refined as the best players from AudioNote, or even Jolida. Overall the imaging and tonal balance is very good, with varied, but quality source material.
I would love to see some ProAcs or perhaps planars, if they are not obscenely power hungry, in the system. FIrst I will
probably see what some well chosen tubes can do to warm up the sound, especially that of the digital front end. A killer cdp or SACD is definitely high on the list. Suggestions are welcome, I know there is vast room for improvement, but it doesn't suck. I actually only have a total of about $ 3,400 in everything, all bought new at the time except for the Linn.
I would get a used Conrad Johnson pre-amp, a PV12A will be a good choice: the phono section is quite good. As for an amp, it depends on your speaker, musical choice and room size. The C-J will work with almost any amp. I heard your 1b speaker and it is very good and a pretty good match for tubes, so I would concentrate on the amp rather than changing the speakers. Of course a C-J MV55 might fit the bill or a Musical Fidelity SS could be a good choice as well. This set up will really smooth the sound and should give you enough power for anything. I had a C-J for years and it never gave me any trouble so I love them.