To be fair, Foo Fighters might be the most stereotypical response for a 30-50 year old white guy that I can imagine. We can play that game all day and it serves nobody.
I would go with Richard D. James personally. For my money, his output in the mid-nineties matched the greats of the 60s, he more or less invented/mastered worthwhile new genres that have had massive influence on virtually everything considered innovative/fresh these days, reinvented himself each album, is responsible for every aspect of the music (and it's such dense stuff, too), and doesn't really have a stinker in the bunch (one of those guys where different troupes of people could consider any one of his peak albums his magum opus). And his two 2000s+ albums are both very solid as well. I have no knowledge of technical ability (and I imagine he doesn't fair well in terms of sales), but I couldn't really care less about that. I think he's accomplished the most musically.
He's the only modern-ish guy I can think of whose albums consistently hold their own against the greats of the 60s, his understanding of music theory is immaculate, and may be the single most important influence on boundary-pushing modern music (especially electronic-ish stuff). Things like Death Grips, Radiohead, Boards of Canada, and Flying Lotus owe everything to him. And, just purely on an aural level, the work/sound is completely worthy of that and flat out BETTER than anything these guys do, IMO.
Would rate them like this:
Selected Ambient Works 85-92 - 3.5 (Great)
Selected Ambient Works II - 5.0+ (Untouchable Masterpiece)
I Care Because You Do - 4.5 (Brilliant)
Richard D. James Album - 4.0 (Flawless)
Drukqs - 2.5 (Good)
Syro - 2.5 (Good)
+ a crapload of side projects with varying degrees of success
For the sake of comparison, prime Beatles would be something like
Please Please Me - 2.0 (Positive)
...
(bunch of albums I'm not too into)
...
A Hard Days's Night - 1.5 (Neutral)
Help! - 2.5 (Good)
Rubber Soul - 4.5 (Brilliant)
Revolver - 5.0 (Masterpiece)
Sgt. Pepper's - 4.5 (Brilliant)
The Beatles - 4.5 (Brilliant)
Abbey Road - 3.5 (Great)
Let it Be - 2.0 (Positive)
Not very far off for me at all.