Recommended Axis & Allies alternative rules / variations?
One Hit Infantry

For advanced players, the overarching strategy of A&amp;A reduces to the infantry push mechanic as described in Don Rae's excellent essays--this is especially true for 2nd edition games, which have 3/2 tanks vice 3/3 tanks. 

The essence of the IPM is that Germany and Russia should buy only infantry until the late game, after they have fortified their borders with infantry and established dead zones in Eastern Europe. The US, UK and Japan also play IPM, but after a short delay to build navies and/or factories to move/spawn all this infantry. 

IPM works because the opportunity cost of all units is higher than infantry's (i.e. infantry are the cheapest unit in the game and are twice as effective on defense as they are on offense). Cheap means they are the only units you can ever afford to leave in a dead zone (i.e. open to counterattack by a superior force). Their effective defense means they are most valuable in large stacks that can devastate an attacking force with insufficient "cannon fodder".

Don suggests a brilliant and simple solution to the stalemated and long-developing game common between experienced players utilizing IPM: modify infantry so that they attack and defend on a roll of 1+. 

This change takes some getting use to, but after only a game or two becomes second nature and dramatically changes the game for the better. What was once a defensive stalemate becomes a furor of attack and counter attack. 1/1 infantry means a one-on-one combat between two lone infantry becomes a fair fight, it means any additional attacking force is statistically overwhelming, and it means infantry alone defend so poorly as to be almost useless. All of these factors bias the game just enough in favor of the attacker to prevent large stacks of infantry from materializing. This change also makes a fighter-only vs. infantry attack feasible since the odds that the infantry will score a lucky hit have been cut in half.

Beyond the traditional sitting around a table method you can try out this variation on the computer if you are lucky enough to have a copy of the out-of-print Iron Blitz (you can edit the infantry attack/defense values); it's also trivially easy to implement if you play-by-email.