Good.
Good. Now make that search box more visually appealing. Now it's quite plain. Remember that it's one of the key features of your site. It's should be eye-catching and attractive. Make it to match the rest of the site. Add CSS to the editbox and button.
Good. You could keep it though in just the pages that actually had a sidebar with a conditional. Anyway, no harm done, it was pretty useless IMHO.
I didn't doubt the search function. I just wanted to make you realise the importance of keywords. Make keywords obligatory.
Nice. Now make them a little nicer. You're a web designer, remember? (I saw that in your profile).
Quite useless imho but nice thought.
It is ;)

I only had a quick look but one thing immediately bugs me - it's a personal gripe of mine that many share - I hate fixed width forums - it just about fills the middle 50% of my screen, with great bands of wasted space at the sides.

I LOVE fixed width!! :D
I will eventually make my second site fixed width as soon as I find time...

Regarding fixed vs. fluid designs....

Both have advantages and disadvantages. I've heard good arguments from both sides of the camp. Most of the time I personally prefer fixed because it seems more readable at 760px wide. More like a standard A4 printed page. When fluid designs flex beyound 760px, it looks odd to me unless you have multiple columns. Probably the best example of a fluid width design I can think of is www.sitepoint.com. It's fluid and very readable.

In the case of PhotoSharingForum.com, I couldn't find a way to make all the pages look nice with a fluid template. Maybe I'm not skilled enough as a designer, or maybe I'm just lazy :D

I appreciate all the feedback you guys have given me. It has been very helpful!