So I ended up going with First Axis and Infantry Attacks. I did not go with DR or AK as I do believe that there is a larger secondary market for those and since I don't play regularly (about once every 3 months on average), the chance that I will play one of those scenarios is small.
IA seemed like a no-brainer at this point since some of those maps are used in the supplements I have/ will receive (Workers & Peasants, Edelweiss and the soon-to-receive Power of the East). Plus, this will give me an opportunity to try the IA rules without resorting to "building" my Chihuahua Incident (GC download game)!