Get an HP, I like HP. Vaio's are extremely overpriced and Sony tends to use WAY too much proprietary spam on their PC's. Sony has a record of making things that only work on their hardware, components that don't work in other PC's, etc. Never had an Acer, but people say they're bad. Don't get a Compaq, my friend's Compaq had a failed hinge, a dead CD drive, and some other hardware issues. My new HP is nice though.
I'd definitely look at HP, I have a dv9700t and it runs great.