Isolation transformers - where do I start?

Trying to get into power isolation. This idea seems to have merit because there seems to be less irritating high frequency distortion late at night than in the daytime.
So where do I start?
1)1 big 2kVa isolation transformer? Plug everything into it?

2) PS Audio "ultimate outlet". Plug everything into it?Reduces common mode noise by 40dB.

3) Sola constant voltage transformer 60 VA for the CDP and preamp (which draw 30 va each- I play music very soft - 1/2 watt output on the power amp - so probably much less than that).
- "Highly regulated sine wave outputs with harmonic distortion less than 3%"
- "Output voltage regulated +/- 1% with input voltage fluctuations of +10%/-20%."

4) Power conditioning shielded C-V transformer 140VA for CDP and PRE:
- reduces common mode noise by -120 dB / Normal mode noise -60 dB / <2pf capacitance between input and output wiring.
- Output regulation +/-3% with inout fluctuations +10%/-20%.

5) Get 2kVA for system and also smaller 60 VA for CDP only.

Is a power conditioning transformer ($250 for .14 kVA)better than just an isolation model ($250 for 2 kVA). I realize small capacity so only for CDP or preamp.

Any suggestions would be appreciated.