I own every studio album on CD (plus additional copies of several on vinyl, cassette, and even a couple 8 tracks!), the major compilations, the official live albums, the digital-only EP, quite a few 7" singles and 12" maxis, and a handful of cassette-singles.
Solo-wise, I own on CD -- all of Stevie's & Christine's albums, all of Lindsey's except 'Seeds We Sow' (I have a digital copy, but haven't feel the need to purchase a hard copy), five of Bob Welch's, three of Mick's, two of Rick's, and Bekka & Billy's one-off album. I have digital copies of many of the other solo albums, as well.
That's just the official stuff.