It can seem out of hand, but it depends on what you are using things for.
My wife and I have four notebooks and there are currently three desktops and two NAS boxes in the house. There are uses.
Macbook Pro 15" (new, June 2009) is my new machine, mainly for field work with Photoshop, but I also purchased it for video editing which I have been doing.
Macbook (white) is used mainly for a mobile Pro Tools rig. I couldn't pass on it; I got it dirt cheap.
Fujitsu T2010 is my wife's main notebook, and she uses it for her graduate classes.
Dell Latitude X1 is old. Still a great machine, and there is nothing more portable and usable. Samsung had a great design for that machine.
Windows Vista destkop (Quad-core, 4gb RAM, 30" monitor) is our main desktop, and I use it for Photoshop and Illustrator mainly. My wife works from home on it on occasion.
Windows Vista HTPC (AMD X2, 4gb RAM, 52" 1080P monitor) is our home theater compliment to our FiOS STB. Vista's Media Center is top-notch. We can stream Netflix, see Microsoft's television content, and I have my entire DVD collection on my NAS. Rather brilliant.
We have a small, fanless PC running Windows XP that we use to print-share a label printer and a photo printer. It was also driving a custom made photo-frame, but unfortunately the LCD finally died and I have not replaced it.
The two NAS boxes are 4tb each (RAID 5) and contain my media as well as a backup of pretty much everything digitized we have custody of. One box mirrors the other box.
I am hoping to replace the main desktop with a Mac Pro at some point and dual-boot the machine with Boot Camp.
We could do without the Macbook and the Dell Latitude at this point. They get used the least. However, I still prefer a dedicated desktop (I like multiple internal drives for what I do) to compliment a laptop. Sharing a laptop with my wife? Not going to happen.
I am just happier since Boot Camp is available. My wife despises Mac OS X. I am indifferent between the UI in Mac OS X and Windows Vista/7, but it makes life in Pro Tools much easier to deal with and Snow Leopard = True 64-bit has me excited.
I did just pre-order four copies of Windows 7 (two Home Premium for the Fujitsu T2010 and the HTPC and two Professional for the desktop and the Macbook Pro). Not a bad deal at all ($50 and $100 each for the upgrades, respectively)