What's my next upgrade? Please advise.

Hi Folks. I'm wondering what my next upgrade or equipment switch should be and would value any advice or tips. I'm pretty happy with the sound I'm getting but I guess I always have the upgrade bug. My system is as follows:

Audio Physic Virgo Speakers (very latest edition - single wire/not biwire).
Sonic Frontiers Line 3 Preamp (with upgraded Siemens tubes)
Blue Circle BC2 Hybrid Monoblocks (75wpc Class A)
YBA CD1 Alpha Blue Laser CD Player
PS Audio PowerPlant 300 (giving me problems so not using it just now)
3 Shunyata Sidewinder power cords (Amps & Preamp)
2 YBA Diamond power cords for CD player and CD power suppy.
Stealth Triple Ribbon silver speaker cable (8')
Homegrown Audio Silver Lace 1meter inteconnect.
Harmonic Audio TruthLink 1meter interconnect.

Room size is about 18x14

Many thanks,
John.