Re: best basic theme to use as a basic to create a new theme?
If you want a full-width page, I suggest using The News or Feb12 theme, of those in the Tiki 2 package. Or you could have a look at Themes_for_TW2 and choose one that's closest to the look you have in mind. All of those themes are pretty similar in terms of CSS file organization and how they use templates. The themes that have a centered rectangle to hold content use a table in tiki.tpl. Otherwise divs are used for main layout. Post here or at themes.tw.o if you have further questions. I've been meaning to update the documentation for making/adapting themes (at themes.tw.o and doc.tw.o). It's pretty out of date.
-- Gary