Actually the Acers that I've dealt with (several) have little preloaded software to speak of. Usually just the dvd burning software, Norton trial, and their recovery stuff. They aren't terribly reliable however, I would recommend a better brand such as HP/Compaq, Toshiba, ABS, Sony, etc.
I haven't seen any benchmarks for the 7400gt so I can't say for certain how good it is but I'm fairly sure the x1600 is going to be faster.