Next Monday is the last episode already, but if this doesn't result in at least one proper season no later than next year then this will be the greatest fan cocktease and the greatest waste of potential of all times.
Because it's awesome, that's why!
I'm only on the third season of the original series so I decided to hold off on the new episodes just in case there's anything spoiler-y.
Why does this series have to be so long dang it.
They do pick up on a number of themes that were established in seasons 1-9 so you could get spoiled indeed. And you would miss out on a lot of tasty references, too.
Everyone now calls it simply Season 10 instead of other names they used before and it's best to consider it as such.
It's a tough call to make. Individually some monster of the week episodes were the among the best in all seasons, but the mythology is what really made the series. And the mythology episodes were so great when tied together, at least until the point when even the writers seem to have gotten lost in what was really going on.
I think somewhere around the midpoint I switched my view on the series--in that I really started to prefer the monster-of-the-week episodes rather than the mythology ones which just kept adding layers of crazy that was impossible to keep track of.
Well you just missed out on the greatest series of the 90's of our youth. Do yourself a favour and watch it all from the start now that it's available in glorious HD.
I didn't watch a lot of original series X-files, maybe 5~6 episodes, but I really liked the first movie.
The movies were just all right compared to the rest really.