As for Gimpshop...
I tried using it a while ago. Didn't work well for me as it was pretty broke.
But if you play around with Gimp's settings it's pretty usable.
I did a screenshot of how I use it typically. Although on my laptop I have limited resolution and generally like to work on my desktop which has much more space. I have to comprimise with my docked dialogs on my laptop to get it all on screen.
Most of everything is affected through the file-->preferences settings. Very flexible.
I am using 'small' theme. The windows hinting is set to 'utility' for the toolbox and 'stay on top' for the dialog box.. This way they float above the image I am working on so I don't have to alt-tab to find the window I want to click on. Having the hinting set to 'top' can cause certain dialogs be obscured behind one another, which is irritating. 'Utility' seems to work out.
Also got rid of the menu bar (more easily accessable via right click) so that is less annoying. Got rid of the scrollbars since I use middle click to move the image around. Got rid of the ruler bars. Set the non-image part of the background to a exactly neutral gray. (on my desktop i use a more neutral gnome theme then I use on my laptop).
Also for real painting and drawing I like to work in full screen mode (F11). So it's intended for picture viewing, so I have to modify the behavor to make it usable for working. I think all I did was enable it so I could see selections, the dancy ants thing. That goes away when you enter full screen mode usually. Since the toolbox is set to 'utility hinting' it stays visable in full screen, while the dialog boxes disapeer.
Also for the toolbar, moving the tool options dialog from that to the my docked dialog boxes on the right allowed me to make it much thiner then normally you'd be able to do.
For actual drawing I use a wacom pad. To use that you have to configure X in a special way and enable extended input devices in the Gimp dialog. That way I get pressure sensitivity and can select a different tool for each imput device.. (like erasor or smudge for the "erasor', draw or brush for the stylus, etc)
Little things like that make it nicer to use. Of course you'll choose differently on how to set it up.
I am also using a beta version.. 2.3.10 right now. From Debian Experimental (either install the package manually or use pinning to allow you to install individal programs from other repositories). Has some bug fixes, some usability improvements and performance improvements.
see for how it looks like:
http://img88.imageshack.us/my.php?image=screenshotkx0.png