I did recently compile a list of infantry innovations of the inter-war and WW2 period and came up with the idea of creating a complete list, spanning the whole documented history of at least Europe.
Minutes later I gave up, for that's a subject for a doctoral thesis - not for a private project.
It did nevertheless remind me of how poorly we are informed about Europe's pre-historic period. The equipment of the Alps glacier mummy "Ötzi" came as a huge surprise to modern people when it was discovered a few years ago. He carried no dedicated warrior equipment, though (copper-bladed axe, dagger, longbow, quiver and arrows came close, but were still dual-use items).
The best look into stone-age warfare is probably a look at what we know about native Americans from both Americas in the 16th to 19th century. Much of their equipment was organic and will thus decay just like almost all stone-age equipment in Europe already did. The Maori/Polynesians, Australian Aborigines and Micronesians/Melanesians are also excellent sources.
Native American shields are of especially high interest to me, not the least because I don't know about stone age shields in Europe (the oldest ones I know about are examples from bronze age Greece and the rather ceremonial Northern European Yetholm-type shields.
Native American war shields were both a warrior's (dubious) protection and a very spiritual thing.
Such an item could change the whole idea of how pre-historic combat looked like in Europe. Shields would make less sense if the dominant weapon were javelins, while they would make perfect sense if bows or melee weapons were dominant, for example.
edit 2015: To clarify: The Native American war shield was for protection, while the medicine shield (we'd call it "ceremonial shield" in Europe) was or is about spiritual affairs.
more info: http://www.snowwowl.com/naartshields.html http://www.snowwowl.com/histplainsindianshields3.html.