Since I’m usage-blogging, I thought I’d repost my remarks from last year about this, especially now that we have comments enabled. My verdict on “Although”: It’s perfectly permissible English, but I hate it, to a degree irrationally disproportionate to its (slight) inferiority to “though.”
I know reasonable minds may differ, but there it is. “‘Though,’ not ‘although’; ‘on,’ not ‘upon'”; that’s my motto (though one that may admit of occasional exceptions as to “upon”).