recommendations, please.

I've always had good luck here:

http://www.musicstack.com/

Discogs marketplace has been really good to me of late.

http://www.discogs.com/sell/list

Depends on what genres you're looking for--

but for all-around new/used I always recommend Gemm.com

amazon and ebay, by far the best.

I agree on Amazon for new, in-print stuff. Cheap prices and shipping. Ebay is good for picking up run-of-the-mill used stuff cheap. But I tend to think Ebay prices on harder-to-find stuff just tend to get a bit out of hand. For that kind of stuff, I find Discogs to be generally a lot cheaper and you don't have to hassle with the auction deal.

But yeah, for different genres, especially more obscure genres, sometimes you are best off finding a website that is more speciality oriented.

Thanks! I found what I was looking for at a reasonable price at both discogs.com and gemm.

Any of the above better for reggae, older stuff?

Ernie B's Reggae is hands down the best reggae selection online, new and used stuff, fantastic prices. Order more than $50 worth and you qualify to get a wholesale number, which only really saves a buck or two per record, but if you'r ordering a bunch might as well.

Ernie B's Reggae

Yeah, Ernie B's is great. I bought a bunch of those Trojan 3cd boxes from Amazon used through Ernie B as well.