The bottlenecks IMO are the speakers first, then the CD player. I'm a dynamic speaker guy, so I'd suggest looking at nice sensitive full-range speakers like the Coincident line (or even better, FAB Audio if you can find them). Better speakers driven by those wonderful amps will need a better source, and there's lots of good stuff available. I'm partial to tube-output, non-oversampling, unfiltered DACs like the Audio Notes, but there are lots of excellent DACs out there that would give the old Rega a shot of audio vitamins.
Oh yeah, and some TG Audio cabling to ice the cake.