As far as the chains go, I'd say my singular 5 guys experience put them at the top of the taste heap, but with a couple of caveats. I found 5 guys to be very expensive for what it is. It has the feel of a cheap, bare-bones, self-serve kinda place ( didn't invest a lot on decor, that's for sure ) but the prices were about 1.5 X what I'd spend at Licks and 2X what I'd spend at Wendy's or wherever. As far as the burger itself, I have had at least a dozen better tasting burgers at smaller 'one offs', most recent in memory was Woody's Burgers at Lakeshore and Brown's Line.
I used to really like Lick's but they did two things which most places do eventually : 1) They changed their burger "formula" ( this happened a long time ago...burgers became less garlicy which I found made them less enjoyable ) and 2) they jacked their prices. I can understand the price increase since food prices seem to be spiralling out of control in the last few years, but after changing the way their burgers taste, I find myself eating there about once a year just to see if the "magic" has come back.
Lately, I have resorted to making my own kick-ass burgers. Sometimes ( correction, MOST of the time ) I'm not in the mood to pay $12 - $15 for a burger and fries, so have a night every week or two where you make the biggest, kick-ass burger you can....blue-cheese, mushroom, zucchini, jalepeno,salsa goodness ! Oh yeah....