We are all faced with this dilemma from time to time.
One bike we have an emotive attachment to, the other is a practical and usable tool.
I am in the market for a new bike next year, I am torn between waiting for the BMW f800s and a thruxton. One is far more capable than the other but there is something about the thruxton. (BTW) I am english so that might explain it.
I think it is the same way for you and the Buell. But let me share with you my logic everytime I look at a Buell. After the initial wow that looks really nice, no valve adjustments and a belt drive, I can't get by the HD engine.
Everytime I see a Harley or Buell I can't help thinking that there is an angry farmer somewhere wondering where his tractors engine has gone.
Think of it this way, if you where buying a brand new buell and the salesman said "What v-twin shall we put in it for you sir, the HD, suzuki or Ducati?". I'm willing to bet that it is only the CPA turned bad boy biker (read middle age crisis -- which I am in BTW) that would choose the HD.
Consider what you want to use the bike for. If it were the occaisional romp through the canyons on a sunday, after church of course

, then I would go with your heart, but you are talking about commuting. You want something with balanced power and torque, comfort and cheap maintenance. ALthough bike maintenance is not cheap I would have to come down on the Z.
Sorry Buell, I love your designs but the mill just doesn't do it for me.
P.S. Just to gussy up the thread, you know, to get things moving, I would like to propose that helmets should be optional, but electing not to wear one should entitle your insurace company to reclaim all medical expenses from your estate. There, you have a choice, but it is not without consequence.