day trip from Tokyo - Kamakura or Nikko?

Which would you recommend as a day trip from Tokyo - Kamakura or Nikko? We're going to Japan in late July, and the day we have earmarked is a weekday.

Kamakura is a better day trip from Tokyo. It is easy to get to, just take a Yokosuka Line train from Shinagawa Station, and it's about 50 minutes. Nikko is great, but is better suited as a 2 or even 3 day trip.

Nikko is obviously a bit farther than Kamakura, but easily doable on a day trip (i've been twice, once with the Tobu express direct from Asakusa, once with JR Tohoku shinkansen and chnge at Utsunomiya, a bit longer but free for JR pass).
IMO, Nikko is much more impressive, since it's a quite small town in the wooded mountains, and shrines are absolutely gorgeous, magnificent, and colorful...
Kamakura has a great Buddha and lots of shrines an temples, but the atmosphere is more city-like...
but again, it's only my point-of-view... ^_^

I think it depends on what part of Tokyo you're departing from. Also, Kamakura is by the sea while Nikko is in the mountains.

I should have been more specific. You can take the Yokosuka line from either Tokyo Station, or Shinagawa Station, depending on which is closer to your accommodation.

I am just on my way back from a three day trip to Japan and I have been to both Nikko and Kamakura. It all depends how much walking are you prepared to do as well. I loved Nikko because it has very impressive shrines and they are very easily reached on foot. Kamakura has places spread all over the city. However I have found the architecture in Nikko more original. Hope that hopes.

Sorry, was supposed to be three weeks trip... Lack of sleep on the plane ;)