They'll have DVB-T ("Freeview"), DVB-S2 ("Freesat HD") and analogue tuners. They're also required by EU law to include a common interface slot which can be used to add pay DVB-T channels (Satanta) or if the tuning functionality allows it (non-Sky) satellite pay TV channels, but I doubt the latter.
An integrated Freeview/Freesat EPG would be very good, giving easy access to the channels that are exclusive to each platform but I expect they'll be kept to separate operating modes.
The ability to output from one digital tuner while viewing on the other would be nice for people with only a VCR or analogue tuner DVD recorder and no DTR.