Just saw on their blog that widgetbucks are offering a couple of new look ad types. Not a major departure from where they were previously IMHO. Personally, I'd like to see some options that weren't as 'heavy' or 'chunky' looking. At this stage WB ads are next to impossible to blend into a site.
Anything that requires effort to hide amongst site content isn't very good where I'm standing. Yes you'd like to make some cash, but you don't want to have people distracted by ads.