I agree wit' the aspect that both classic and high-tech weaponz has their own strengths and weaknesses. And very frequently, they cannot be measured the same way, for instance, if the goal is other than pure destruction.
A good example for this is a flamethrower vs. an ionspray. The Zicca ionspray is technically a high-tech variant of the flamethrower, or some sort. Comparing the two will clearly signify that both can be useful and useless at certain situations. For instance, a flamethrower can cause great fires, which continously burn for a very long time, effectively wounding or killing anyone crossin' the flames' path. Ionspray cannot do that, however, ionspray can work under-water, where a flamethrower can't. Flamethrower is also ineffective against undead or spiritual hostile entities, whilst the ionspray can erase'em out of existence with ease. As for firing range, a flamethrower wins over ionspray once again, so at large open areas, flamethrower proved to be much more successful, whilst the ionspray works better in close quarters combat.
As for HE weapons, using a bazooka or a missile launcher on close ranges means certain death. Energy superweapons, however, leaves the wielder unharmed, such as the BFG.
Bayonets are always very cool, and are unimaginibly useful when you run out of ammo, and there'z no time to reload. Same goes for rifle butt strike - very few games utilize them. At energy weapons, it is understandable, as their high-tech design never really takes bayonets into account, and their structure makes it undesirable to use the empty rifle as a club. Just take a look at the Doom 3 machinegun.
Basic energy weapons are mostly "pew-pew lazerz" or plasma, and yes, they're in for the nice effects, albeit
some of these sci-fi firearms has very unique effect. The Displacer from Opposing force was an extremely thoughtful armament, which could teleport you to Xen. The Deviator from the Dune universe is another brilliant weapon, which turns enemies against each other. The Paralyzer can stun multiple enemies in a large territory for quite a period. As for the Dark Matter Gun, the concept of a superweapon which passes thru enemies (and is NOT a Railgun) was something really notable. Oh and I loved how the mini black-hole dragged the evil Strogg backwards while they squirm and fidget

And of course, the Railgun itself was also a brilliant creation, the sniper rifle of the future. The Tesla gun is also fine, especially in GTA 2, where you can damage multiple targets in one shot.
The Aliens pulse rifle was indeed a crossbreed between conventional and energy firearms. The Half-life pulse rifles however, are operating entirely on energy.