I was using a pretty nice K2 scheme for a while (unfortunately, I'm not at my home computer now, so I can't tell you where I got it), but the other day I switched to the System Theme mentioned in this very forum just a few posts before yours.
I like it better than the K2 scheme. Tho' it's taking a bit of getting used to having more than 256 colors. But the buttons are better in the theme than in the scheme (for example, in K2, all buttons were "lit", whereas the theme has only the default button lit). Plus, using the OS built-in system seems a bit snappier overall than K2.
Not to say that it's perfect, and there are things I like better with K2, but for a nice Aqua look and feel, I highly recommend this theme.