I'm a bit partial to macbooks since thats what I'm on, but honestly anything with a good processor and ram will do. Battery can be a bit of a cpu hog sometimes, but I've used all of those VST's (and more) in a setup without any problem and I've only got 2GB ram. the intel core 2 duo lets ableton work wonders. Remember also that there are features/tricks in Ableton that can allow you to get even more power from your machine. By freezing tracks that aren't going to be changing that much you can virtually temporarily eliminate the CPU being used by a certain VST. If it's a good deal, go for it. There is also an absurd number of free VST's for PC's.
On a side note, you're going to spend almost double on getting the same specs for a macbook that you will the Acer, but I have on clue about customer service for Acer.