If all you are going to do is scrapbooking with it, go for the Mac, really that is what they were built for. Laptops are expensive no matter what if they are worth a darn. Lots of good arguments here and it sounds like you are already decided (just need ammunition for DH)! Just note that programs like Photoshop/Elements/ACDSee etc do tend to take a while longer for the newest upgrades to come out. But unless you HAVE to have it right away...they do tend to come out.
That being said I'm a PC girl. I've had two dell laptops with minimal problems (both lasted over 3 years with me constantly using them. I did just have a graphics card die on me after 3.5 years, we ordered a new one, followed instructions and it worked immediately. But in the waiting...we also ordered a new laptop, this one:
Alienware M17x with 8gigs of RAm and a 500gig HD (I use externals mostly)and a super duper graphics card and the fastest processor out there. But all of this is overkill mostly due to my DH is a gamer and it will be "shared" between us. But most of the time it will be my AWESOME machine. Oh and we installed Win7 on our computers now and LOVE it so far.
And yes after the last commercial about Macs not getting viruses, they started popping up. So if I were you Mac users, I'd be all "nod nod wink wink" about that so they don't "hear" you! LOL
But like I said, if you are straight up going for only scrapbooking, then go for it, just expect to pay $$.