What Rune and Meteorite combinations offer me the most effective blades?

Solution 1:

Gwalhir is one of the best (if not the best) steel swords in the Enhanced Edition, so if you can buy that it will last to the end of the game.

You also get a very nice Silver sword at the very end of chapter 4. Both of these swords are much better than even the best crafted swords, but since you can't do anything else with those runes, you might as well craft a silver sword to use during chapter 4. You can find a list of all of them here: Rune Swords

Personally, I like one Moon + two Earth runes for a mix of extra damage, knockdown, and sensitivity to silver.

Solution 2:

Pertaining to a previous comment:

"Personally, I like one Moon + two Earth runes for a mix of extra damage, knockdown, and sensitivity to silver,"

Don't you mean 2x Moon Rune + 1x Earth Rune? This would yield +75% knockdown, +15% overall damage, and +30% silver sensitivity, where 2x Earth Rune + 1x Moon rune would yield a blade with 15% less sensitivity.

Conversely, it is my firm belief that the latter rune combination is more effective than the 3x Moon Rune sword, although not as "pretty."

Although this sword would be effective throughout Chapter 4, it is not really a make-or-break moment in your attempts to slaughter monsters. At the end of the chapter you get this sword from the Lady of the Lake:

Aerondight
Damage + 60% Attack + 10% * Chance of critical effect: Pain + 50% * Chance of critical effect: Blinding + 50% * Chance of critical effect: Incineration + 50% * Chance of critical effect: Precise hit + 50%

This is clearly not even comparable to any rune combination sword.