My company matches 100% of the first 6% you contribute, then another 50% of the next 6%. So if you put in 12% of your salary, they contribute another 9%. I thought that was pretty awesome until I saw some of the other matches on this thread! Still, a 9% pre-tax "bonus" every year is nothing to sneeze at. We also have excellent insurance coverage (our HDHP, with a $4000 family deductible/$6000 oop max is $204/mo for my family of 3, and my company contributes an additional $2000/yr to my HSA.)
I'm always excited at review time, because every raise I get means the company puts more money in my 401k :)