General Discussion

A base zankautou wouldn't stand a chance against a lightsaber, but I'd prefer a shikai or bankai any day. 

As much as I hate to say it,    the  Zanpakutō is a pretty powerful weapon. Granted, aren't the abilities of the sword based on the spiritual prowess of the wielder? So if you're spirit power is crappy, so is your sword? 

@sickVisionz: Thank you for saying what I meant.  T_T

@takashichea said:

" You forgot the force. I think the force is a deadly ally with the light saber and it will crush any zanpakuto except for Kenpachi Zaraki. Don't mess with him.Forgive me for being wishwashy. "

But we aren't really talking about Shinigami vs Jedi, just one weapon or another. So ignoring kido and force... 
@SuperperfectCell said:

" @AgentJ: But even base Zonpakuto varry in power, Ichigo's sealed Zonpakuto is much "stronger" then the genearic Zonpakuto that low ranking Soul Reapers carry around. i think Ichigo's sealed form could match it. "

I would disagree, but until Lucas Arts and Shonen Jump merge, I guess we won't know for sure.  
What I do know is, sealed swords are essentially big chunks of steel. We all saw what Qui Gon Jin did to those blast doors in episode one.  
 
Would Kira's shikai have any effect on a lightsaber?

@AgentJ said:

" @takashichea said:

" You forgot the force. I think the force is a deadly ally with the light saber and it will crush any zanpakuto except for Kenpachi Zaraki. Don't mess with him.Forgive me for being wishwashy. "

But we aren't really talking about Shinigami vs Jedi, just one weapon or another. So ignoring kido and force... 
 

That is the question.  Now lightsabers are normally only used by Jedi and Sith because utilizing them without cutting off your own body parts requires force sensitivity.  If you're using a lightsaber you've probably got some force powers.  In fact, from what I understand, a Jedi (don't know about Sith) builds their own lightsaber as part of their training.  On the other hand, a  Zonpakuto bonds with their wielder increasing their skill and abilities.  Can an average person even use a Zonpakuto?  I don't remember enough from the anime and I don't read the manga to answer that. 
 
However, lets say that Travis Touchdown comes along and he can pick up both a Zonpakuto and a lightsaber but still has none of the associated powers that normal coincide with handling the weapon.  I think because of its ability to cut through practically anything, you have to side with the lightsaber.  It's compact and stylish, too.   
 
I found this odd cosplay video on the web mixing the two franchises. 

@sickVisionz:  Yeah, I guess there are a few examples but apart from slicing open a tauntaun's belly, there aren't that many.  Because a lightsaber is not like a normal sword it's thought that force sensitivity is required to effectively use one in combat.  A lightsaber has no weight in the blade so it's more like fighting with a flashlight than a standard English longsword.  Such bladed weapons can weight between 2 and 5 lbs.  I haven't seen enough of the cartoons to make any reference to those, but the case for General Grievous is a curious one.  From what I understand, he's basically a brain and spinal column inside a mechanical body.  I've heard some say that for a body to be able to live on after being reduced to so little is a sign of the force; however I also remember reading that the more machine that's added to a person the less attuned they are to the force.  Now, Grievous was taught lightsaber combat directly by Sith master Dooku and being mostly a machine, he might not worry as much about lopping off a leg while fighting.   
 
EDIT: While it's hardly an official resource, I found this post on "Ask a Jedi" explained it best.  It corrects several of my misinterpretations and addresses the cartoon and expanded universe material, too.  Can a non-force users wield a lightsaber?

@cfatalis said:

" @AgentJ:  It makes something weight twice than before, so the handle will get increased in weight "

Wouldn't he have to slash the handle for that to be the case though?

Can a lightsaber do this?
 










A zanpakutou can.

A cool zanpaktou>lightsaber 
lightsaber> a crappy/mediocre one