I decided to check how my Goomburra skin rendered in some other browsers and the result was... pathetic. So I've delayed my deployment to try to fix this up. Really my only problem is with the menu. Currently I'm using the solpart menu - basically because that's what DotNetNuke uses, but after looking further into it I've discovered that it seems to be a constant source of problems for DNN skinners.

If anybody has a suggestion for an another free ASP.NET menu system then let me know with a comment (if it works for you... the current commenting UI doesn't always work - something that will be fixed with Goomburra!)