Better hardware creates a more stable environment for an OS. I do own an IT support company and can tell you, the issues we have typically revolve around hardware and not software. The Mac OS also has just as many problems arise as Windows. None of our clients using our support setup has ever had a virus either, so to me the virus argument is kind of null and void.
I also would never recommend an HP laptop to anyone, regardless. They have an enormous failure rate. However that has nothing at all to do with Microsoft, which is what Apple constantly tries to pit itself against.
Case in point my business partners HP laptop ran win 7 like crap, his macbook runs it very well, however my Dell XPS handles win 7 better than his macbook.
There is also more to a computer, especially a laptop, than it's core components which needs to be built correctly. Layout, assembly, cooling, wiring, and efficiency have a lot to do with it too.
Again, getting away from the big box laptop companies like HP/Compaq helps a lot. I have customers on 4-5 year old toshibas running win 7 perfectly. I also have another customer with a 5 year old Pro Star laptop (which is a top notch company,
http://pro-star.com/ ) running win 7 and it has never had a single issue.
One has to understand that most computers sold in big box retail stores are mass produced by the lowest bidder and not made for much more than casual use. Even when you think you are getting a lot of features for a good price, just run the other way. Something has to be sacrificed.