Hey Guys, great replys.
I do think this is an interesting subject.
As Fearn points out, the 'knife' in whatever form is not going to replace the 'gun' as we know it, and similarly, the technology we currently use in projectile weapons is unlikely to ever be replaced by 'star trek' style directed energy weapons for the simple reason that 'guns' are simply too cheap, reliable and effective.
We may see advances in bullets, propellants, a revisiting of the HK Caseless tech etc, but essentially guns work, and they work very well while being durable easy to use.
But thats not to say that a 'combat' blade has no place.
Sorry David,
I can't see light sabres ever being a reality

Well, beyond my master-replicas version!
Too much power needed, too many containment problems, too dangerous to the user etc.
But I can see us developing technology that blurs the lines between organic and inorganic. Blades 'grown' with a cutting edge a few molecules thick (or a single molecule) that would be able to split anything they are used against with ease, and if they are chipped or damaged, 'healing' in their scabbards while not in use.