Totally missed this. I love Zen Arcade, and it's the first Husker Du album, I heard, but I'd think Flip Your Wig would be the ideal entry point. The second side is a little heavy on filler, but the first side (that would be the title track through "Games") is probably the greatest run of songs in their whole discography. So maybe get that one next.
For many years, I considered Warehouse my favorite album by them (and one of my favorite albums, period), but, in retrospect, it's not as consistent as it could be. I turned a friend on to Husker Du using it, though. He liked it so much that he asked if it was some sort of HD greatest hits compilation.
And since the Sugar recommendations's out there already, I'll also toss in Bob Mould's Workbook, his first solo album, which throws out the Husker Du formula completely for acoustic guitars, cello, and strategically placed electric solos. Absolutely amazing. And the follow-up, Black Sheets of Rain maintains that slow, contemplative mood, but adds thick layers of Crazy Horse-style distortion.
On the general topic, if you can get Husker Du on vinyl, do it. The albums were never properly mastered for digital media. My old cassettes probably sound better than the CDs and MP3s.