Nuggets is certainly good, and started a huge revival in it's time, but overall, I prefer the
Pebbles comps. for the more obscure gems of the era. Nuggets can be a great sampler of artists to go find full albums by, while Pebbles contains more groups who never put out more than a single. Since they put everything they had into those one shots, often the results are pretty amazing. How can you do better than a song like "Beaver Patrol"?
Genre related comp. that I HIGHLY (pun semi-intended) reccomend is Crypt record's
Jungle Exotica Vol. 1 This is a really amazing anthology of the meeting ground between the Sonics and Les Baxter, and I'll admit, I wasn't that aware there
was a middle ground before I got it!