^Damn, where's Peter David when you need him?
I'm actually pleasantly surprised at how the poll is turning out to be such a close run thing. I wouldn't even say it comes down to taste because I love both shows and all of their aspects from helium farting Hynerian to spoo ranchers. For me I suppose it just comes down to having a slightly more personal attachment to B5 than Farscape.
Oh and Greg, if you have the opportunity, I'd highly recommend watching B5 from start to finish. There are several threads knocking around the board where posters have chronicled their first watch through and to date it's always been a positive experience. Even if you've seen most of seasons 2-4 there's plenty in 1 & 5 to enjoy plus I can attest that when I went back and saw the show for a second time I was genuinely startled at how much of the myth-arc gets laid down in the first season (and even the first few episodes.) There's a surprising amount hidden in plain sight which, just from a writing stand point, I can't help but admire.
As for Farscape, oddly enough and in total contradiction of my previous statements I loved that there was no real plan beyond a vague direction here and there. The show was able to improvise, invent on the fly and retain an adventurous sense of spontaneity that's much more difficult in big "arc" shows.