Looking at version 7.0.2, I would have to say the three features that Lotus points out on their website are the most interesting to me.
The first one to catch my eye was the one about running Notes on a USB device. I tried it and thought that it was pretty cool. I mentioned it to a couple of other people at work and mentioned that it stated that this was only for the Notes Client only, not for Admin and Designer.
Well I got a note back from one of them that Declan had posted a way to add both Administrator and Designer to the USB device. As I do have the full Notes-Designer-Admin client loaded on a machine I jumped over and grabbed the four files Dec mentions to copy for this to work and presto, worked like a charm. Makes the whole thing that much better. If you have different ids depending on what you are doing, possibly one for regular use and a separate one for doing administration tasks, simply make sure that you copy all the ids that you might need over to the USB device as well.
Of course, depending on the capacity of your device there are numerous possibilities of having your data with you to work on it as well. Of course, if doing so these days you may want to think about the security of such data.