Visually, your style isn't great but it's not that bad either. I'll start with the logo, I'm not to keen on logos which have been centered as it doesn't give it any kind of intergration with the rest of the style unless you have opted for multiple colours and blending it into the background colour in one form or another. I would possibly go with a 2 part image and have some kind of repeating graphic and/or opt for something which has a border that sperates the logo from everything.
Colour theme looks a little saturated, maybe this was the look you wanted? I noticed the colours are basically based around the same colour variation. I would opt for a 3 colour system (implement another colour) that would showoff the style better. In it's current state, the same colour gives off an awfull bland feeling.
The forum Icons should be replaced with some custom images, Images which are relevant/consitent and will complement your style and theme. Re-coloured vBulletin stock images to me look worse off than the stock images if they hadn't been re-coloured.
Same rule goes for the other and many re-coloured stock vBulletin images which have been re-coloured. vBulletin may have provided the psd but the way the psd is structured you still can't perform a proper re-colour implementation.
Personally, I'm not all that keen on the whole look of your site but I'm sure with experience the styles you produce will get better (unless this was a pre-made style) in that case, I would suggest you change it.
Goodluck with your forum.
