I second the font size suggestion, I cannot read the sidebar links and the search is tiny because you used a 9 or 10 (maybe even 8) pixel size either on the sidebar div or in the ul and li or the link or all of them!
Best to simply just declare one font size in the sidebar, apart from the h2 which is called by default and I size medium. I'd favour 'small' rather than ems or px or %.
Its a good black design, but perhaps the dashed lines, sized perhaps 3px around your div or paragraphs, might look less good as you go on. I don't think the borders cut it for most websites, unless you put borders everywhere. You can use css to give some fancy discreet borders, especially a post devider.
Work on the text sizes - most people sprinkle the WP css file with too many text size statements - I have myself but am ammending it.
Also, do a few sample pages and posts using up the common html mark ups such as lists and bold and so on. Add images so we see how they rest.
It seems a steady enough theme, all works as it should.
As for making it widget ready, fair enough, you won't have any arguments there.
When you start a theme, you half hope you'll release it the next night, but it will take a few weeks for most people.