I rode a friend's fixie one day. We did a 12 mile loop. I was in love!!!
I had him convert a Motobacane Nomade to a 42 x 18t (63") and have
been riding mostly fixed ever since. That bike has since been redone.
That was about two years ago. I currently have four fixed-geared bikes:

The Nomade now has a 52 x 18t
The Motobacane Mirage runs a 52 x 16t
The Van Dessel has a 44 x 16t
and my newest (ridable as of yesterday) is a Schwinn Le Tour with a 42 x 16t.

I'm working on a Lotus Elan now. It will run either a 52 x 19t or a 42 x 15t, depending on the hub and chain line.

My longest fixie ride was 67 miles over lots of hills in North Carolina on the VanDessel.