Just went to both sites and they look fine to me. I'm using a retail Radeon 8500 and the Plutonium 8.1 ("optimized" Catalyst 2.3) drivers.
Aha, I bet I figured it out. I'll bet you're using IE huh?
I use Opera as my browser and both sites look 100% fine. I decided to fire up IE (6.0 with sp1, I'm running WinXP Pro, sp1) and see what they look like. The Starcraft sitewith IE looks like sh*t compared to Opera. When you scroll the white text dims and when you stop it un-dims.
The Gamespot site looks OK to me on IE though.