I am also interested in a client for Linux, as I use Ubuntu full time when I'm at home. Currently, when I need Evernote, I lug around my old iBook G4 with me, which just sits next to me on the desk with only Evernote open.
Running under WINE worked while I had a free membership, and was only using it lightly. Now that I sprang for a Premium membership, I've been using Evernote a whole lot more (went from 40-ish notes to over 250 in a day or two), and the drag and drop functionality for assigning tags and putting notes in notebooks is pretty buggy. The client would freeze constantly when trying to move more than one note at a time.
The web interface is good enough for light use, but when I start to get into heavy use for tasks, etc. I end up hitting a wall with the functionality. What I would like to see is an Adobe Air (or QT, GTK, etc.) implementation through the API that includes all of the functionality I love in the Mac client, but would be completely cross platform. I wish I had more time and energy to put into creating such an implementation myself, but alas, I am a poor college student