Definitely. Worth it.
I first followed this story in the pages of the late, lamented Warrior, where it appeared in black and white - a format that suited David Lloyd's moody art brilliantly. Then, of course, being such an excellent mag, Warrior went under. Luckily, DC soon picked up the series and released it, coloured this time. It was the first time a comic story really made me think, and re-reading it recently I find that the story has really held up well over time.
Most of all, you need to ask yourself: is V a terrorist or not? And why did you answer the way you just did?
Anyway, definitely a worthwhile purchase. I don't know how much of Alan Moore's work you've read, but, along with the Marvelman story (aka Miracleman) and the Bojeffries Saga (a quirky tale about working-class genetic anomalies in the UK), also from the pages of Warrior, V For Vendetta is one of Moore's early masterpieces and still stands comfortably on par with later career highlights like The Swamp Thing saga or Watchmen.