Consider adding a graphic. Your header looks 'lonely'! Also, you're missing out on an opportunity to monetize your site. Think about adding some AdSense links, or text links to a ClickBank product. For example, on Zak's tech shop, I'd add links to tech products that are being discussed. Hope this helps!
I do not like the color scheme, I think you should add more colors into the color scheme and add some graphics into the header.
I think it needs some pictures and maybe a statement about what type of community it is so people know right away what they might want to do or talk about.
Well PHPBB always remain the best ever free forum script and I love their new and innovative designs - Regarding talkaville I would like to say that it's nicely categorized with good information for the beginners . I think you are on the right way and I would like wish you best of luck for the future growth of this site ! Regards, Gnoc