Doepfer

Hi
This is my first post as I have just acquired my first modular system secondhand.
Which consists of...

1xRS15 19" rack-mountable 6U case
3X RS-95 Voltage controlled oscillators
1X RS100 Low pass filter
1X RS110 Multimode filter
2X RS60 Envelope Generator
1X RS70 Inverter/Preamp/Slew
1X RS170 Dual Multiple
1X RS40 Noise/Sample and Hold Oscillator/Clock
1X RS20 Ring Modulator/Multiple
1X RS165 Signal Mixer
1X RS180 
2X Doepfer A-178 Theremin controllers


Can anyone recomend some basic modules that would cheaply and effectively enhance my 
system. Nothing too exotic though.

I've been thinking of
Another VCA.
1x Dedicated LFO
 RS50 Trigger generator with VC pulse shaper & VC DC level shifter.
Another envelope.
and the big spend a RS140Midi / CV Converter.

Doepfer alternatives would be appreciated.
Kind reagrds 

David