2 weeks notice is the way to not burn a bridge with said job in the off chance you want to go back later on down the road. Whether or not that job rehires you is another story, though.
I'll admit, there was one job I didn't put my two weeks notice in. That was Walmart, I was fed up after working there for six years and not getting recognition. All my other jobs I did put my two weeks in, it's best not to burn any bridges.
I feel like it's best to not burn any bridges, but I also feel like it's important to put it in and actually work out the 2 weeks (barring any unforeseen circumstances, of course). I've worked with a fair number of people who put in their 2 weeks, but on their last days, they'd just call out, and I felt like it just made them look bad. Of course, if you don't care about burning the bridges, then it doesn't really matter.