I use win 7 at work and os x at home. I like os x better. I find win 7 freezes and has to be rebooted a couple of times a week and sometimes a couple of times a day. This is not the fault of win 7 per se, it is the fault of our IT guys who insist on cramming so much corporate junkware on our machines.
But based on my experience with my work machine, win 7 is worlds better than xp but still exhibits behavior I rarely see in os x, some of which are: freezes, failure to sleep/resume properly (there is a hotfix for this from August that our IT guys apparently still haven't comprehended), nuisance popups telling me my bluetooth is not discoverable, nuisance popups about my wifi status, things I must click on to move on and get work done, glacially slow performance as soon as any MS app (office 2007) is launched, complete system freeze at the launch of adobe reader (and yes I have adobe reader for "probem pdf files" on my mac and it isn't as disruptive), ie 8 STILL vulnerable even with the latest security patches (I use firefox for surfing anything that isn't behind the corporate firewall), slow boot time.
I wouldn't say you shouldn't get win 7 because of what I've seen because I'm sure it could be done better than what our IT guys do, but I can say I wouldn't choose it after what I've been through.
As for hardware cost, Dell and HP aren't very good values. I tend to like Lenovo (formerly IBM). In the end, Apple hardware tends to cost more because it is the only (official) way to get OS X but also because the industrial design is second to none (ie mag safe, keyboard layout, touchpad, etc), so for me it's worth the higher cost to stick with Apple gear.
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