A quote from http://www.globalsecurity.org/security/ops/hsc-scen-3_flu-transmission.htm
"Some analyses report that influenza typically has a transmission rate of about 10. But others suggest that flu is not as highly transmissible in a community setting as has been imagined. The R0 for the 1918 pandemic was estimated to be only 1.8 in one study, while the 1918 pandemic strain's R0 was estimated at around 2 by another estimate. According to another analysis, the estimated proportion of the population with A/H1N1 immunity before September 1918 implied a median basic reproductive number of less than 4. Another study estimated R0=1.89 from influenza case incidence data for the first wave of pandemic influenza A (H3N2) starting in July 1968 in Hong Kong. These results suggested that the reproductive number for 1918 pandemic influenza was not large relative to many other infectious diseases. Other recent estimates of R0 for seasonal and pandemic flu typically range from 1.5 to 3. Estimates of the reproductive number (R) from England and Wales (1958-1973), for a mixture of influenza types and subtypes, ranged from 1.4 to 2.6. In contrast, SARS had an R0 of 3 (excluding super-spreaders), and measles has an R0 of 10 to 15, pertussis (16 - 18) or polio (8 - 12)."
Most extimate the Ro for Ebola at around 2