In case you win in a lottery and have too much time to do this – here are some conductors BOXSETs worth checking out. Some are ltd and no longer availble or out of print/stock, some are simply expensive. Your site already contains many of these recordings but still all sets contain rare material otherwise hard to find or not availble or prev unreleased – so here we go:

Abbado – LONDON Symphony Orchestra complete recordings on DG and DECCA
Böhm – Complete orchestral recordings on DG
Boulez – The complete ERATO recordings
Boulez – The conductor complete recordings DG and DECCA
Davis – Symphonies DECCA
Jansons – The Edition w/Choir + BAVARIAN Symphony Orchestra
Masur – The complete WARNER classics Edt
Mehta – The complete COLUMBIA Album collection
Mehta – complete DECCA recordings
Mehta – The complete WARNER recordings
Ozawa – The complete WARNER recordings
Solti – The LONDON Orchestral recordings
Solti – CHICAGO The complete recordings
Zurich TONHALLE celebrating 150 years anniversary Set