To really change the look of the forums you'll have to do some editing by moving things in the top part of the forums.
You could install the Advanced Color Control MOD which will allow you easier choosing of colors and easy insertion of images into the table headers (the dark blue rows on these here forums).
A MouseOver effect (I think Crash calls it the "Hover MOD") on the rows on default.asp and forum.asp might be nice too, but you shouldn't use that if it makes your forums crowded.
Both MODs can be downloaded at the Snitz Exchange (link is in my signature).
Adding different icons can really help too. I have a couple sets on my site on the Snitz Stuff page. You could also look on the net or create custom icons if you don't like the ones on my site.
OneWayMule once made a "delphi-mod" (version 3.1 sr4) that made the forums look very simular to the forums at Delphi.I tryed to go a step further with this mod becaurse I really like the Delphi-style, but at the end I screw up every thing. Its basicly just hard HTML work to reorganise the HTML part of the asp-files.