This is tending to become very much a poll on fictional series only. Understandable, but I thought it was a bit broader than that.
That said: a comment about I Claudius, which was my no. 1. I was riveted by it all those years ago. Bought it about ten or fifteen years ago on DVD. Still gripped.
The thing is, you can see it's been made with a bag of crisps and a packet of Smarties — the budget must have been laughable. The sets are a joke, the music (such as it is) is confined to heralds playing the same pre-recorded bit which sounds like a cow in labour. The costumes are the kind of thing you might get for Christmas when you were ten (if you were lucky).
Everything — everything — rests on the screenplay, which is brilliant, and the quality of the acting. Brian Blessed, Siân Philips, John Hurt, Derek Jacobi (in the performance of a lifetime), George Baker as a wonderfully creepy Tiberius. Oh — nearly forgetting Patrick Stewart. A small oversight. Just a phenomenal team performance, with two bits of wood and some papier maché as back up.
I can understand a) that a lot of people on here would not have seen it first time round, and therefore never, and that b) in the wake of the epics revival with things like Rome and Gladiator, with all the sophistication that implies, people might not be able to get past the visual hokeyness of it. I lent the DVDs to a much younger friend a few years back — somebody who appreciates good acting — and he just couldn't get past that. I am, though, rather disappointed that it's placed relatively low. I didn't much care about any of my other choices. But that one, I did.