That is a BIG question Patrick!
I would hate to make the choice of army for someone else. I suppose it depends on the following:
1. Your own interests
2. If you have any political affiliations
3. Whether you like the particular uniforms of one side or another
4. You want to pick the 'Winners' side
etc
etc
There is probably slighlty less uniform variety in the French Army than in the Grand Alliance.
The predominant French uniform colours is grey/off white although their Gurad and foreign regiments(of which there were many) have a wide variety of coat colours. French flags are dazzling colourful but are again predominantly of the same pattern - white cross on coloured or white field 9except the cavalry)
The Alliance armies use many heraldic symbols and coats of arms on their colours and the designs are far more varied.
You could pick a force from a very large army like the French or Dutch or you could do the entore army of a smaller state such as one of the German City States or Principalities.
The theatre would make a difference too. The English and Dutch mostly (but not exclusively) fought all over your own country!
I would recommend reading a few battle accounts.. that will fire up your imagination.. try and choose army/units that served in several different theatres and then you have flexibililty to move then around!
Look in the WARCHEST section of the site there is a downloadable source list which is a bit haphazard but has lots of reference material indexed.
