Seems like a decent design, and I prefer leaving the main text on a white background like your new effort. For me the blue background seemed a little too strong, and it made reading the main text difficult, though that may well be my monitor, or the poor lightly in this room at the moment.
I have to say though that all the buttons, to me at least, look ugly. Some of them obviously have a place, but my personally view is people will Get Firefox if they want, and the button on your site is not going to get clicked. And I can't really think of anything more ugly that the google adds that don't match the colour scheme at all.
The banner at the bottom for "UK Model Railways Web Community" doesn't look brilliant either, and certainly black text on a deep blue background doesn't.
As above, the thumbnails could do with being a little bigger, perhaps upto 200x200px, although thats easy to say at 1280x1024px when there looks to be plenty of room. Arguable for anyone still having to put up with 800x600px, they would probably be the right size.
Certainly nothing really wrong with the page, my comments are more my personal preference.