I'll give you some of my favorites off the top of my head for what I feel are exceptionally good sounding recordings.
Primus\Les Claypool - While none of their stuff sounds bad by any means, anything recorded at Les' "Rancho Relaxo" studio sounds awesome. The BROWN album indeed!
Metallica - Garage Days Re-Revisted Raw, natural and heavy as hell. Newsted's bass tone is to die for on some of these tracks. This recording captures the sound of the guitar cabinet better than the overly polished studio recordings.
Heathen - Victims Of Deception. Here's an example of a very processed sound, but it really works in this instance. Very full and rich sounding crunch guitars.
Led Zeppelin -
"When The Leeve Breaks" - The heaviest, most weighty, earthy kick drum ever recorded. When the guitars and harmonica kicks in it can be a bit harsh, but I can't get enough of that kit!
Melvins - Gluey Porch Treatments\Ozma. It's pretty raw and primitive, but the Melvins come closer to sounding like what a band playing in a room sounds like. Excellent naturual ambience, especially noticeable on the drumkit.
Kyuss - anything. Kyuss practical exudes "analog tone" from its collective pores. Warm, punchy, very excellent recordings I think.
Trouble - Self-titled 1990 Rick Rubin did a nice job on this one. It has a very warm, pleasant tone while still kicking ass. Trouble doesn't need to be extreme to get the point across, it just sounds plain HEAVY and MEAN.
Sinister - Cross The Styx. Extremely technical and grinding death metal. But the difference is that the engineer was able to keep it all under control even though there's 5000 notes per minute! This one sounds MUCH better than any of the later releases I've heard. Maintains detail without obfuscation.
Rush - Caress Of Steel. I would say most of their albums are great, but I especially am in love with the almost palpable, feel-the-drumskins sound of the toms on this album. Warm and woody.
Overkill - The Years Of Decay. Humongous wall of guitar comes to knock your walls down. Thick, controlled crunch. Very nice. Drums are a bit clicky, but there's much worse!