I'd go with Parklife and Modern Life is Rubbish if you want to start with their britpop period. but if you're more into rock/alternative influenced stuff, I would recommend their self-titled record and then 13, which are my personal favourites. they are really worth checking out. :)
i refuse to participate in any modern flairups of the rivalry between them and Oasis cause it represents the worst humanity has to offer (British culture and Gen X nostalgia ) but you gotta hand to blur that with the exception of Dave they are much cuter and more breedable than Oasis.
In some ways I consider it a more honest album than the rest of them. Even if people say they're trying to emulate shoegaze, it'll always seem more like an album they wanted to make, more than an album their record label thought they should make. Until self titled at least.