IE6 is on life support. The latest update I could find says IE6 had only about 20% of the market as of February.

I've mostly ignored IE7 up to this point, because as a corporate developer I have remained bound by all of the limitations of IE6. But since IE6's demise seems eminent I decided to do a quick review of what we'll gain when it finally bites the big one.

1. Alpha channel PNG support(I've been avoiding transparent PNGs until now because the IE6 work around was such a pain)
2. :hover on all elements not just on anchor tags (Woohoo! no more rapping DIVs and images in anchors)
3. Width and Height Min/Max supported (is it Christmas?)
4. CSS2: first-child, adjacent, and child selectors
5. CSS3: attribute selectors: prefix, suffix, substring and the general sibling selector
6. About a million bug fixes....

For full details I highly recommend this August 2006 IE Blog post about IE7 and you may also want to read this February 2009 one about IE8 to see where we're headed.