i'm a big fan for streamlining the interface, as we've talked about in the past.
(and i think 2 downloads for dif versions is also something to do away with).
i like the idea of a simple resizable interface which has a main text edit and maybe checkboxes for what results are wanted. the commercial program wordweb is absolutely worth checking out - it is as streamlined as can be and it is attractive and very usable.
the idea of having different results from different dictionaries in dif tabs would be one neat idea.
or having all results on one screen would also be nice.
i think in general i like the idea of having a very minimalistic main interface, with other options offscreen or tweakable on demand, so im in favor of the idea of editbox, checkboxes for where to search, and then clean results.
and as someone who is curious about words i really would like to be able to just type a word and click GO and then have all info on the word displayed from the different sources (ie dictionary, web, thesaurus, quotes, etc.). not sure how practical that is, but it would be fun.