I'd take them ALL if I had more room. I really love the "dashboard" style and if I hadn't gotten into the treadles, I'd go after them.
For now - I've got a collection of Singers, I've tried to keep them all unique in some way - and I've got a few I'd bring home if I found them, but I'm not seriously looking.
My other goal was to find one of each that fit the 12 Boye shuttles offered in the very early 1900's. And while looking around I found a book with a list of the "Major" manufactures in the early 1900's, so decided to get one of each of those too- but there was a lot of overlap between the two lists.
I also love lock stitch/chain stitch machines, though the hard part is usually getting the chain stitch adaptors for them.
But my real obsession is with attachments. I've only got a few of the rare/expensive Singer ones that I'm missing - but I keep finding more older attachments I've not seen before.
I'm trying very hard to keep my interests in the "modern" style of sewing machine - the ones that most people wold look at at easily tell it's a sewing machine. The oldest of these are from the late 1800's. My collection sort of takes up where SteveH's leaves off. I think the older ones are very neat and love looking at them.
My goal is to get a decent setup and then start going to quilt shows and vintage shows with a display of working machines.