Hi paul,
Your image sizes are fine, well below what broadband can handle or 56k. Looking at the code behind your site it looks quite good, I cant see nothing obvious wrong, I take it this is a template which you are updating with the text. What are you using for doing that? Sounds like server issue, let us know.
As for the web changing over the next five years, yes it will but remember that your customers come from all ages of life.
Having a website with loads of flash, high image sizes is fine but will
all of your customers be able to see it or be bothered to wait for it?

Untill 56k is dead you still have to cater for it. Keep it simple, professional and to the point. Hopefully they will brighten it up after you have finished with the text and make it a little bigger, it is rather small and dull.
Hope it goes ok.
Mark