The default theme in 11.04 really blows when using eclipse or other IDEs. The new style scroll bar is extremely irritating. It makes it very difficult to see what position you are in an editor pane and the "pop up" widget you have to grab to scroll doesn't always register properly. That stupid scrolly is one of the first things I remove. The default theme colors also make the scroll bar background a similar color to the part you grab on standard scroll bars, again making it difficult to find. I could list 100 things that are irritating but that's a matter of opinion and in any case, anything that's annoying or retarded can be disabled, configured or removed if one desires.
I think you'll find using eclipse on a netbook with it's tiny screen, gimped keyboard, minuscule trackpad and wimpy atom cpu to be a crappy and suboptimal experience. There are truckloads of full fledged mini laptops that would be way more suitable for such purposes that compete with netbooks on price. I'd look there first.
