The Doctor In The TARDIS

Whats the fascination with this era? I think other than contemporary earth its probably one of the most visited in the shows history. Off the top of my head its visited or referenced in:

Silence In The Library/Forest Of The Dead
Talons Of Weng Chiang
The Empty Child/the Doctor Dances
Time Of Angels/Flesh And Stone
The invisible Enemy
The Girl In The Fireplace

And probably a load more. Add to that its the era where Jack, John and Gray are all from as well as Magnus Greele and where River seems to spend most of her time when not with the Doctor (and where she dies). Didn't they also find K9 in the 51st century?

It's not an issue or anything, just something that they seem to fall back on a lot thats easily noticeable.

The Invisible Enemy, I believe, is described as "about 5000", so more or less, but it's a rather anomalous 51st century where humans haven't yet left the solar system.

I wonder if the reason for its use in NuWho (as opposed to the 50th or 52nd, for instance) is that it's 3000 years from now.  Other than that, I can't think, unless it's just a go-to laziness.

In The Invisible Enemy they say that 5080 is when they have the 'breakout' or whatever it's called where humans finally spread out through the galaxy, so perhaps as an era where humans are exploring space travel a lot more its a good point for that type of story or something? Just a stab in the dark guess. To be honest I'd not noticed that they particularly spend much time there.

Also, four of the stories listed in the OP are Moff stories, so it might just be one of his personal favourite times or something?

It does contradict most of the rest of the classic series, though, when Earth rules a substantial part of the galaxy by the 26th century.

RTD used to say that the reason he used the same names throughout a lot of his shows (Smith, Tyler, Jones, etc) was so that he could get a grasp on the character while he was writing them because it made more sense to him that way. Perhaps the same could be said of this era with Moff??

This is a good train of thought, and I think perhaps the most likely. If you want a futuristic setting then it makes sense to go with what you know, especially if you want to avoid conflicts with canon and stuff like that.

Perhaps as well by going to the 51st Century you are nice and clear of any social/political predictions as to how the world may turn out? With it being so far away you aren't going to end up with any "Tenth Planet" style discordance with Antarctic mission controls for the British Space Programme in the mid 1980s

That's ^^ a good point actually. A lot of the stories from the classic era that are set in the present(ish) day don't actually fit history and while that's no fault of the show or the writers, setting things 3000 years in the future means that anything that doesn't fit is unlikely to matter. Unless of course the show is still running then :P

Isn't The Beast Below in that era too when they are all leaving Earth?

I thought that was earlier, but I may be wrong.