I find Press This in it's current form useless. I guess I could save a link with it.. but I can't do anything else.
However, if it could function like a shared link on Facebook - auto-generating a thumbnail of the primary image on the page (FB actually gives you the option to sort through thumbs, if there are more than one) and maybe even a short summary.. now THAT would save you some time.
[Granted, the summary is just icing - easy enough to cut/paste that - but snagging an image, re-sizing it in PS, uploading.. all this makes posting a quick "Hey look at this!" link to something you found pretty tedious work.]
When I find a cool article somewhere and want to share it, I just click the "Facebook" link and it takes me to a page that grabs all the info for me (and leaves me room to comment)..
Now, if Worpress had something like this (be it Press This or some other third-party app) you could easily create a template for these "quick link" posts as well as an archive page to display them (I'm assuming here that you will want to use styling to take the auto-snagged info and that this will probably be different from your "normal" post layout, which would generally consist of images larger than thumbnails) and add these quick links to your site.
That's that part.
More importantly, it would be FANTASTIC if you could at least add custom fields in Press This (as it stands, the lack of this option alone makes Press This useless for publishing new posts, for anyone for which these are a required part of their design.