Topic: 'Post new topic' + 'Post reply' + 'Quote' location - heat maps
If you look at any 'heat map' for a website (e.g. http://www.useit.com/alertbox/reading_pattern.html), the eyes follow an 'F' pattern - scanning starts at top left and moves right.
Given that 'Post new topic' and 'Post reply' are going to be the most commonly clicked (?) links, would it not make sense to have these positioned in the 'hot' area - left of screen? I find the current position at far right a little difficult to pick out quickly - especially on wide-screen monitors - and it takes my eyes away from the content that I'm reading.
Similarly, 'Quote' is going to be frequently clicked and it should be located closer to 'Post' because they share functionality.
For topics, I'd advocate that 'Post' + 'Quote' are located in the dark blue bar, directly above / below post body. For forums, I'd recommend 'Post new topic' is located in dark blue bar, to right of 'Topics [ n ]'.
Also, while I appreciate the understated design of PunBB and don't want to see it become strewn with icons (a la every other forum in the universe), I wonder if 'Post' is important enough to get its own eye-catching icon?