The definition of "PCs" is rather broader than I thought when I first read the question so...
In the house: two desktops, three laptops, three iPhones, one iPod Touch, a Nintendo Wii, a Nintendo 64, two Nintendo DS's, an HP iPaq. Plus whatever I'm repairing for friends and family at any given time.
In the loft: a desktop, an Amiga 500, a Dragon 32, a Binatone (the orange one with the twisty-knob controllers), a 48K Spectrum, a Mega Driv a PS1. I'd still like to add a C64 to this collection at some point... I've never had one.