Hi Lenny
If you've invested in a Naim Nait and Focal speakers, then yes, you should definitely get a dedicated CD player - the Pioneer DVD is fine for movies, but won't do justice to the Naim/Focal kit with music.
The Naim CD5i is a very good player (we gave it 4 stars), and would work well with the Naim amp. It has a rich, refined sound with a smooth (but not bland) treble and decent midrange. But a couple of rivals just edge it for detail retrieval.
Alternatives? I'd steer you towards the Cyrus CD6s (£650), Cyrus Roksan Kandy MkIII (£650) or the Arcam CD192 (£900).
All are reviewed in the Ultimate Guide to Hi-Fi, on sale now.