Which ruleset will depend, to some degree, on what you would like to get out of the games. WW1 battlefields were much more compressed than WW2. Unit frontages were much less, by a quantum. A WW1 company would have the same frontage, roughly, as a WW2 platoon for example. This makes WW2 rules unsuitable unless heavily modified. The exception will be where you are really familiar with a WW2 ruleset and just want something that allows WW1 figures to be used instead of their WW2 counterparts.
At one stand per squad level, consider using Crossfire. Ground scale is not an issue and the fire/movement tactics work perfectly well. No turns or measuring are added bonuses in my experience. You can get a flavour of an early war game here:
link
At one stand per platoon level, there is Crush the Kaiser as Alan mentioned. I haven't played it but have seen it being played. Looked absolutely fine.
At one stand per company level, there is Great War Spearhead (GWSH) and Square Bashing.
In all cases, the number of stands on table will be approximately the same. GWSH isn't 'really big' in this respect but can scale up to multiple armies (if you have enough tables ;-). See this link for an example of a really big game (not recommended for the faint hearted):
link
Most GWSH games are around one division per side (but covering the same frontage as a brigade of their WW2 counterparts).
If you want fewer figures in total then it might be better to consider a skirmish level. Otherwise you loose the flavour of how WW1 units had to manoeuvre in close proximity to their neighbours and with the concern of long distance (i.e. well off-table) weapons systems.
Robert
rebases some old soldiers.
