Lots'a spoilers ahead, I don't recommend reading beyond this sentence unless you have seen the finale... and most other episodes 2005-2007.
Okay I watched the finale... definitely not as good as 2006, which is a shame because David Tennant is really good as the Doctor. Wait, I think everything about the 2006 season was better then both 2005 and 2007. Doctor Who needs to learn from their past and from what other successful series are doing at the moment - if you look at the first doctor he's stories are very different from say the 3rd doctor, because they changed the direction of the show. But more then direction and format, they need to reinvent the show. This is why South Park is still on the air. Like 24 - which I discovered with the fifth series.. and now that I've seen all (except series 4, but I'm getting there) - I still believe it's the best out of all of them - but with that said series 3 was much better then the first two, and it's largely due to the fact that 24 reinvents itself, and doesn't assume that they'll just keep their target audience by doing the same thing again and again. I'd say series 3 was the second best out of all of them (not counting series 4 as I've only seen the first few episodes of it).
Another thing they need to do is bring it to Australian TV sooner. They did this last year, but I wasn't going to wait until July this year - it's a fact that Australians are the leaders in downloading TV episodes, and it's largely due to the fact that we don't get to watch the dammed series on television (that and they cancel shows). If they had started mid-May (or maybe even if they let us know when they would eventually broadcast) I would be watching them on TV instead (of course, I may still be tempted to download the 2nd part of a 2-parter.... if it was really gripping).
And a Saturday night timeslot???? They really need to secure a better timeslot.
Personally I would like to see the series split into two 25-minute episodes per week; I think that would work much better then one 45-minute episode. I'm sick of the fact that so many TV series are so long; I get impatient now with movies that go longer then 120 minutes (except very good drama movies like say The Godfather... or Zodiac - loved that movie). I don't mind watching a lengthy documentary...
Anyway, technical aspects aside, I don't think the writing is anywhere near the standard it needs to be. There are also things which really don't make any sense - like walking straw-men... oh sorry I mean scare-crows. This was somewhat tested in 2005 with the first episode, but all in all they don't contain any energy which they can use to move - like a car without fuel. Dalek was a terrible episode. None of the dalek episodes thus far have truly shown the dalek's cunning; they plan and have contingency plans, and would probably set out a decoy before the real attack! And they should have a TARDIS of their own; I mean they've had one before!
They also lost my suspension of belief that the Master couldn't get the TARDIS to work. "Locked it's coordinates permanently"?? So how did he expect to unlock it later and travel at will? - A sonic screwdriver is still only a screwdriver, it can't unlock something with a deadlock - so it can't lock something with a deadlock either. Meaning if the Doctor could unlock the coordinates later, then so could the Master. There was way too much of taking the doctor out of the action to make his fate dependant on others in this series, it was a cliché.