The Strokes - Is This It. It was definitely important then for kick starting the indie-rock revival, although its impact has dulled since then
I’d also argue Dizzee Rascal - Boy In Da Corner for giving UK rap a great big kick up the bum, although I don’t think its impact was as worldwide an impact as ITI.
There are quite a lot. Maybe not in a Srg Peppers/Dark Side of the moon sort of way (as in huge hits at the time that loads of older people blinded be nostalgia fawn over it like it was the best thing ever)
But maybe like Loveless a moderate hit at the time but seen as a masterwork of its style. Sure most people on the street will not tell you that Loveless was the best album of all time but for many music fans and critics its seen as up there