Someone correct me if i'm wrong but the ATI x600 is PCI-Express already so that means it's upgradable... it's a no brainner vs the nVidia. The rest of the hardware he can pretty much upgrade to fit the Aspire 1711's specs later if he wants to.
Compaq = Athlon XP-M 1.8Ghz (2500+)
HP = Pentium 4 2.66Ghz
The rest is pretty much the same... 512 DDR, 40Gb HDD, ATI 64Mb shared.. though the Compaq has a g wireless as oposed to the HP's b WiFi.
I think the Pentium 4 has more power... but other than that maybe you should pick the one...
I applied AS on my laptop too, the die was in direct contact with the copper heatsink, all they did was isolate the die with some tape, blah... I feel that it's more safe now.
I have one that i use when i'm typing in bed (like i'm doing now) ... it's very light, so not to worry about the weight on your USB port, i didn't notice any diference concerning battery life time either.
The light (at least mine) illuminates the whole keyboard, it's really helpfull when u're...