One of the things I dislike about the default Squeak image, in every version, including the new 3.9, is the Sesame Street looking windows. They're fat and ugly, even with the LookEnhancements package which can be loaded into 3.7 and above, and comes loaded by default in 3.9. This package goes a long way towards making Squeak look more professional, but it doesn't go far enough, and keeps these nasty looking fat 4 pixel borders that make it look like something built for children (which I guess, it is), but just looks old.
One of the things I love about Squeak, is that it doesn't need to please everyone, because there's nothing in the system I can't simply find the source code for, and fix. If I spend any time working in a Squeak I don't like, that's my own fault for not changing it.
So, in a 3.8 image, LookEnhancements is one of the first things I load, in 3.9 it's already there. Once loaded, here's a change set I apply to fix the windows after LookEnhancements has had a crack at them. All it does it slim down the window borders to 2, the splitter borders to 2, and adjusts the positions of the corner grips to match the newer slimmer sexier more professional looking windows. You may have to fiddle with the corner grip offsets depending on your choice of font sizes for the title, they're simply floated over the windows statically, not dynamically adjusted to compensate for changes.
Next, for those of you who develop on Windows, comes installing Andreas's Win32 Native Fonts package from SqueakMap. This almost gives Squeak a native look and feel on Windows. Personally, I prefer Verdana 12pt font for just about everything, so I change just about every font in the system to it. All of these changes are already in my image, but I thought I'd detail a little more some of the things I do to create it, and why.
After making these changes, if you look in preferences and turn off rounded window corners, rounded menu corners, and scrollbars narrow, you'll end up with a much nicer looking Squeak that actually looks suitable for adults who can still see. Squeak might have been made for kids originally, but Seaside has given it new life in the real world, where serious apps are written, and expectations for how an environment looks and feels, is a little higher than what a kid might require.