Not exactly happy with the way Firefox 4 looks and prefer how it was before the upgrade? We found the best theme for Firefox 4: "Firefox 3 For Firefox 4". Here's a sample of how it looks on our computer:
Try it for yourself, in our opinion it's even better looking than Firefox 3.
By the way, many people have complained about the order of "open in new window" and "open in new tab" being switched when you right click on a link. The solution is here.