Feel like I should hear more of Hayes's albums but "Hot Buttered" and the hits comp are pretty satisfying and like you, I don't feel the urge to listen to him very often.
I recently got pretty heavily into James Brown so I'd say he's worth another try (start w/ that 40th anniversary comp). To be fair, a lot of it's pretty similar and repetitive so I can understand folks not being able to dig it but man, I just can't get enough. It's about as effective as an anti-depressant as music gets- I can't sit still while listening to him.
I used to feel the same way about The Isley Bros- that 2 disc "Essential" comp pretty much lives up to its name and a lot of their slower "boudoir" songs tend to bore me (though at their best, they did this stuff as well as anybody). But if you liked the funky style they employ on "It's Your Thing", I recommend the "It's Our Thing" and "The Brothers Isley" albums, which are both very much in that style. And the '73 "The Isleys Live" album is among the best live soul sets I've heard- some killer guitar soloing on that "Ohio/Machine Gun" medley that concludes the set.
The Temptations are one of my favorite groups and the Whitfield era is my favorite but even I'll admit that all of their albums have filler. However, I just love their sound so much even the filler sounds heavenly to me. I'd still recommend at least picking up "All Directions", "Sky's The Limit" and "Solid Rock" in full, but the 2-disc "Anthology" probably has everything the average fan needs.