Your a:hover styles should also be applied to a:focus [0]. You might also want to read about why using only color to differentiate links is bad practice [1].
[0] http://www.456bereastreet.com/archive/201004/whenever_you_us...
[0] http://www.456bereastreet.com/archive/201004/whenever_you_us...
If you'll apply those styles to a page, you'll find that:
* Links are colored. Blue colorblindness is quite rare. That's arguably a far better choice than the orange/red links I'm seeing more frequently now. For myself, I find underlines distracting.
* On hover they're underlined and the background cover shifts.
* On click, foreground and background colors are inverted.
Your point on :focus vs. :hover is probably well-taken, though those have been equivalent for my use.
I've encountered a number of sites with disappearing sub-menus (themselves an arguably broken UI element), where the rule for visibility is :hover of the/a parent element. Which means that when the pointer moves off the parent and onto the submenu, the submenu disappears. LinkedIn has been exhibiting this recently.