Mountain bike:
3x8: 48-40-28 (I have a 24 I swap in for really steep hill work, but the 24-to-40 shift has to be done very slowly and with finesse) / 12-13-15-17-19-21-24-28 made out of parts of two 7- and 8-speed cassettes
I try for a nice 1.5-step plus granny. I may replace the bottom end 21-24-28 with 22-25-30.
Bianchi road bike:
2x6: 50-42 / 14-16-18-20-23-26 (pushes the 1980 Campag. rear derailleur about to its limit)
The secret to getting a decent low gear from vintage racing equipment is to lower the top gear a bit. I have no need for anything bigger than 49 or 50T up front, even less if I had a 12T high in back.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069