Deluge
A feature I really find missing in Deluge, is a column to show how much of the filesize has been downloaded.
You can find this in the details tab, but not in the main screen.
And since columns are optional, anyone who doesn't want the column could just turn it off. (or never turn it on, depending on the default)
Otherwise though, Deluge has a been a perfect transition from Azureus for me; no messy, slow Java -- no locked files when downloading them, etc, etc.
Keep up the good work.