I'll wait while you all finish your chorus of "What the hell???"
There are two big reasons why Flood makes this list. The first is that it's a damn good album. Not "good for They Might Be Giants", not "good in a weird sort of way", but just damn good. Forget the 'hits' for a moment; tracks like Lucky Ball & Chain and Twisting expertly dance along the line between catchy pop awesomeness and too-clever-by-half lyrics that not only define TMBG but a distressingly large chunk of my personality. And Minimum Wage is still the ultimate anthem for anyone who's ever worked retail.
The other reason Flood makes the list is that it was the album that made me realize professional reviewers are usually full of shit. Way back in 1990, when Flood came out, I worked in (you'll be shocked to hear this, I'm sure) a record store and actually read Rolling Stone, and considered it a valuable guide for making my way through the musical wilderness. When they reviewed Flood, however, they gave it two stars and the reviewer spent the entire thing alternately trashing the band for not doing what he wanted them to do, and doing the very things he was criticizing them for (at one point he derided their riffing on pop culture references after he'd described their "Letterman-like smugness", or something like that.*) The upshot was that I decided I just had to hear any album that would piss off someone so obliviously self-centred, and Flood became one of the three pillars** of my theory that most professional entertainment journalists are just in it for the free food and swag.
So, to sum up: Flood made me realize that it's OK to be a freak in sheep's clothing, and that the supposed experts don't know their ass from a hole in the ground half the time. How could it not be in my top five?
* - In the interest of fairness, I dug up that Rolling Stone review online. My hazy memory wasn't that far off. I wonder what David Browne does for a living these days, anyway?
** - The other two are, ironically enough, Little Earthquakes (thanks to Peter Howell's full page glowing review of it in the Toronto Star that made it perfectly obvious he had no freakin' idea why he was supposed to be giving it a glowing review, but she had all that industry buzz behind her so who was he to say any different?) and O Brother Where Art Thou? (which Owen Glieberman in Entertainment Weekly gave an 'F' grade and called misanthropic. What a fucking tool.)