I am a previous HP loyal customer who now buys exclusively Apple. I had two different HP laptops, and have had a slew of desktops (I think it's been 4 in the last 7 years) and it seems like my HP computers had about a 2 year life, if I got lucky.
I got out of the HP laptop game with the first generation Air. I went from a 17 inch HP laptop with the 10-key counter to the MBA for only one reason: my HP was too big and I wanted the most portable laptop on the market. That turned out to be the Air. I ended up not using it nearly as much as I wanted until the last 6 months. During that time, I became very depressed with the battery life. On a vacation with my wife in March of this year, we used it to watch tv shows in our room at night...and we could barely get through a 1 hour episode of Dexter (this was despite having had Apple test it before we left and was told a new battery would be a waste of money, it tested as near perfect).
I had an HP desktop at home that I had purchased last July...it was their top of the line at Best Buy at the time. I started thinking that there had to be a better solution to having a badass laptop with no battery life and a work-horse desktop I couldn't take anywhere and would probably only last me another 15 months (based on previous experience).
What I ended up with was a new i7 15inch MBP with Windows 7 running through Parallels for my own personal psychological security (though I'm proud to say I haven't started Parallels up in over 2 weeks now). I get a laptop that is weighted out as a middle ground between my old HP 17 inch and my Air. I also exponentially added battery life. I was able to eBay my Air and sell my HP desktop to a friend to cover a lot of my cost.
I will say that my feeling of comfort in only having 1 machine now is amazing...and it helps that it's an amazing machine! I have played around with the Envy at Best Buy, and while it might sound superficial, I cannot for the life of me envision that being my primary and solitary computer. Just can't do it. I decked out my MBP with all the "protective accessories" (no lie...hard shell cover, keypad cover, wristpad cover) and this thing leaves the house with me every day and gets used to hell and back every night when I'm at home. My wife and I can now lie in bed and watch a 1 hour television show on this thing and when I go to put it on my desk I'm at 75% battery life left.
I absolutely love OSX being my primary operating system. I had an original fear of having no Windows option in my home, but as stated above, it's use is fading away and quickly. I feel that I have a machine that will last me 4 years or so, and based on my HP experience, I'm going to come out whole financially (buying 2 separate $2000 laptops in the same time frame from HP would actually put me in the hole).
All in all it's personal preference. Why am I a fanatical fanboy for electing to spend more money on what I had heard and read was a superior product? You can shove all the features you want to into a GM SUV and it's still not going to be more reliable than a Lexus. Period. You don't pay a premium (and certainly not an Apple premium) to "fit in". You don't pay a premium to "look cool". While some people might, I'd say the vast majority of people that buy from Apple do it because they haven't been burned by shoddy products and shoddy service and feel that they are getting every penny's worth when they turn over their debit card number.