Best version of the Who theme?

Nothing tops this one:

The Peter Howell one has fantastic drama and dynamics, suits the more tense JNT stuff like Caves Of Androzani very well.

I do have a bit of time tho for the more laidback, clubby Trial-era revamp!

The 12-17 arrangement is iconic. Troughton and Hartnell ones too. Love the McCoy one, very nostalgic for me.
Only original series one I don't like is Trial, which just feels limp to me.

For me, it's a tie between the 1963 and 1980 themes.

The original 1963 theme has this rather dark, eerie, almost sinister kind of vibe to it that you don't really get with any of the other themes. Of course, what the 1980 version lacks in mysteriousness it makes up for with just sheer 80's synth awesomeness.

I'm also rather fond of the theme that David Tennant's Doctor used during his very last season. I actually quite like the really grand, orchestral sound that this theme has. A lot of people think it's a little too bombastic and over the top for Doctor Who, but it gets me pumped up every time I hear it.