I have four:
My two main machines are a Juki 2010 (straight stitch) and a Juki F400 (computerized with all the bells and whistles)--I use both of these nearly every day and they're both set up with projects on them.
I also have a vintage White Rotary, circa 1918--my first sewing machine, bought at a resale shop in Seattle when I was 22-years-old. I keep it in working condition and still use it when the other two machines are in use.
My newest machine (taken out of the box YESTERDAY) is a Janome MyStyle 100--it's lightweight with minimal stitches. I plan to use it for classes and for travel. With a job that requires me to travel, elderly parents in a different state, a fiancé in yet a different state, and a niece and nephew in yet a third different state--I really needed a traveling machine!
I wonder if I'll learn to embroider? Or if I'll "need" a serger.....