Theme development

I am reviewing the simplenews theming and looking for good examples.

From a module developer point of view I am looking for good examples of the best practices of making theme_ functions.
Have found the How to write themable modules to be a good introduction
and found Theme developer's guide but I am looking for info for a module developer.

What do theme developers find good theme_ functions to work with?

When I activate or disactivate any module I get this error. Even if I just click 'save configuration' without changing anything. I have no idea what this means.....can anyone help??

warning: main(./database/updates.inc) [function.main]: failed to open stream: No such file or directory in 
/ (...link here...) /htdocs/includes/install.inc on line 9.

warning: main() [function.include]: Failed opening './database/updates.inc' for inclusion (include_path='.:') in 
/ (...link here...) /htdocs/includes/install.inc on line 9.

I have some unexplained white space in my theme and I cannot get rid of it. I've spent hours and hours in the code and can't find the cause for it anywhere. Can someone please look at: http://genesisdigitalsolutions.com/drupal/ and let me know why there's extra white space at the top, above and below the words "This is a block named "Header" in a divider named "header". Why is there a white strip ^up there^"

Thanks so much!

These pages have a nice collection of general purpose CSS themes canonically identifying the layout geometry:

http://www.code-sucks.com/css%20layouts/faux-css-layouts/
http://www.code-sucks.com/css%20layouts/fixed-width-css-layouts/

I am developing my very first Drupal theme. It itself is really a slightly-styled 'shell' theme, and I have several sub-themes, each depending on the parent theme for layout. These are the files I would like to add in the following order for all sub-themes. For instance:

hi

I am working on a site called http://www.hangoutwith.com and am using Aquasoft theme. I have few questions:

1) How can I make News Videos icon (at the top in the Primary Menu links section) point to Categories instead of Aggregator ? When I click on that icon, I would like it to take me to Aggregator/Categories instead of Aggregator.