naim and whf both frequently highlight Neat Motive as perfect partners for their products but it depends on your budget
i personally found Neat a great product which pairs really well with Arcam so worth shortlisting - i would describe as pretty smooth, great vocals and midrange with good punchy bass but this is on the back of an Arcam system - these are quite dynamic speakers so with Naim will be a fast and punchy but maybe not quite so smooth
i would also add PMC models which rated very highly in my own demos and offer deep bass on their standmounts (not really clearer than Neat but great depth) and good overall balance - i felt Neat had a smoother balance overall but the PMC may work for you and are highly rated all round
and for something a little more forward try Proac - model dependent these are slightly more agile, forward presenting and brighter but again a great brand
the thing is you probably need to really decide whether you prefer a smooth system with great vocals or whether lean, fast and dynamic is your thing - given your first statement i wouldnt be so sure Naim is the right one for you
Arcam FMJ CD36 - Wadia 170i & V-Dac - Arcam FMJ A32 - Neat Motive 3.
Sennheiser HD595 - Little Dot MK III Headphone Amp.
Partington SuperDreadnaught, Chord Epic Super Twin, Van Den Hul 'D-102 III', Tacima CS929, ClearerAudio Copperline Mains.