Time to weigh in on this discussion again.
1. All web designers should have different browsers available to test how their page renders. Ideally the page should appear the same on all browsers (CSS, XHTML compliance is a good start point) but it seems that some browsers choose what to render correctly. The Acid2 test is a good indicator of a browser that can render standard code correctly (with minimal or no browser-specific code).
~ IE7 made a great improvement for standards compliance over its predecessor but it still has some huge issues with parts of CSS code (they don't care about it, so this won't change anytime soon).
~ Firefox 2 is not quite up there - version 3 is under development and the nightly builds have passed that test.
In short, if you're using Windows install IE, Firefox and Opera. They cover the three most common rendering engines out there (including Linux and Mac operating systems). This will make sure that you can test the website across as many possible situations as possible (if you were serious you'd run IE6 and IE7 alongside and ensure backwards compatibility).
2. Colour schemes are everything. A good colour scheme makes a good website better, and a bad colour scheme makes a good website bad. A general rule of thumb is that dark text and light background colours are the best setting for readability. Sure, the inverse may work, but just about all professional websites are dark-on-light, not the other way round.
Background graphics are fine, but there are two key issues here that you haven't addressed. Meshing and readability.
A good background should be seamless. That is, you have no clue where it starts and finishes. Remove that one and find something that you can blend. If you can't, then don't have one. Simple as that. Its very ugly to be able to see the point where the graphic ends because it makes the website look tacky.
The gradient background doesn't work well because it is neither black or white. I see that you've coloured the table cells black to make the text readable but that also makes the website tacky. Remove the bgcolor tags and it will become transparent, from there pick a good colour scheme and it will look a lot better.
Aside from 18 Days' comments, some of which you've already looked into, the only other advice i can give you is to look at some HTML languages. Sure, WYSIWYG is fine on the whole, but there will be cases where you need to do render something a certain way and there seems to be no way to do it through the program. That's when you get down and dirty with the code. HTML and CSS are the ones that come to mind.