I've installed Crunchbang on 3 seperate machines and have come accross thge same problem with Thunar on all 3 of them. Thunar takes forever to load the first and opens multiple instances when its run or an external drive is mounted. Removing gvfs-backends has solved that problem on all 3 computers with the added benifit of the terminal opening in a shorter amount of time. Just a thought but it may be a good idea to add the removal of gvfs-backend as an option in the first time run script or from future installation disks. I've seen mention of this fix in the forums but can't quite remember where, I'm a space cadet.
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If thunar is set to manage volumes then it auto opens a thunar window when a drive is connected, you can disable that in the thunar preferences and i also have noauto for each of the external drives in /etc/fstab.
I suspect corenominal has gvfs-backends in there because many users have NAS drives or network shares they would like to view in thunar rather than at the command line.