737-300/500 - it depends on the cost index, and forecast and actual winds. Above 10000', at about CI25, the FMC speed worked out at around 275 knots for climb and descent. At 10, it was 250 knots. At 40 it was 290-300, if I remember right. This converted to a Mach no of .73-.75 above about 28000'.
Below 10000, if I remember right, the FMC defaulted to 240 knots, so that a VNAV PATH speed excursion of +10 knots on the target speed would not result in a violation of the speed restriction of 250 knots below 10000' in US airspace.
If you wanted to fly without FMC direction, 250/280/M.74 would work out just fine.
I think most aircraft types have a cost index which affects flight management speeds.