in the past couple years, the Secretly Canadian/Jagjaguwar/Dead Oceans family has been pretty impressive.
Beggars Banquet and 4AD are pretty consistently good too.
this year, Sub Pop's lineup is pretty awesome. Grand Archives, Ruby Suns, No Age and Fleet Foxes. I felt like they were slipping a little before, but now they're getting back to putting out some awesome stuff.
Arts & Crafts is another good one.
And I was thinking, overall, Kill Rock Stars has been one of my favorites for a long time. The Decemberists, Elliott Smith, Sleater-Kinney, Unwound, Xiu xiu, Deerhoof...so many good ones.
My favorites lately have been Soundway, Load and Elektra (for some of the older stuff they took a risk on initially and then dumped later cos they got cold feet, like the Stooges, for example).
Oh and I second Neptune's mentions of Stax and Frenchkiss.