David Tennant and other cast members confirmed in an interview with Newsround that, obviously, Martha Jones replaces Rose as the Doctor's companion, they visit Elizabeathen England, go to a hospital on the moon, go to to the year 5,000,000,043, even more distant planets and there is a monster from the past that NOBODY will be expecting to see again...

Take your pick:

YETI
SUTEKH
KRYNOID PODS
MAGNIS GREEL
FENDHAL
SCAROTH
NIMON - Yes, NIMON (BIG FINISH did a nice audioplay with them).

It's what you least expect. Which means something from the last season.

In the belief that if you start chanting something enough it will or won't happen,can I start us with a resounding
PLEASE DON'T LET IT BE THE SLITHEEN!!!!!!!
ETC ETC UNTIL WE SEE!!!!

*yawn* It's the daleks... Eppy 4 and 5. I wouldn't mind them returning, just as long as there is ANOTHER returning villian in the same series.

I don't know if this was subsequently discounted but there was post on one of the forums a while back in which someone claimed that a friend of their's had just had a role as an extra in which they they were killed by a giant crab - Patrick Troughton's Macra anyone?

It's Bonnie Langford - she was a monster

I think it's Cassandra again

Listen to the extract of the Runaway Bride commentary (number 24 on the advent calender at www.bbc.co.uk/doctorwho). Its hilarious! They put feedback on at points which might count as spoilers, but it sounds like they're swearing!