Risk, I find, is much more of a social game that can be picked up and played with friends. Its simple and most people know how to play it anyway. The game is different each time (due to random positioning) and its alot more fun among your normal friends thanks to the ability to form treaties, etc. that can’t normally be done in A&A due to static teams.
That being said, the strategic depth of Risk is very limited. It all comes down to positioning and timing. The nice thing about A&A (but at the same time, the thing that seems to limit it) is the varied unit types. If you want to play a good game of A&A you need five guys that know the rules and are devoted to the game with approximately equal playing ability. In Risk, you can slap together four+ players of decent caliber and you can have a good game.
I like Risk because my friends seems to have a tough time wrapping their minds around A&A and the difference in skill is astounding. However, there is somthing about A&A that makes it so appealing. That somthing is the strategic depth, but I am repeating myself.
I like Risk 2210. Its awesome. Many more options.
I kinda like Risk Godstorm. Its cool to have gods, but I’ve found that 2210 is much more interesting.