Thank God it's not just me...
You don't know how good it is to hear there are others going through the same phenomena!
I currently have 3 bikes: a 1990 Univega Alpina (mountain bike), a 2009 Specialized Dolce Elite road bike (bought September, 2008) and most recently, a 2009 Jamis Coda Sport hybrid. In between, I bought and sold two Specialized Expedition Sport comfort bikes-one was a little too large (we gave it to DBF's father). Its replacement was instrumental in turning me into a bike-aholic. I 'outgrew' it within a few months and sold it to buy the Jamis, which I felt fit the hybrid slot perfectly.
I thought that I was all set, but came across a CraigsList ad in late February for a (local) 2008 Jamis Aurora Elite at an attractive price...and the wheels started turning again.
This isn't a done deal; the bike is not available for viewing until later this month and other respondents are ahead of me. Hard to say how many are serious.
I figure whatever is meant to be, will be. If it is sold before I can look at it, I will not be heartbroken; I obviously have bikes to ride. If I do see it and happen to fall in love again...it will be a tough decision.
There are worse hobbies, I suppose. (At least it doesn't need to be fed, right?)