Adagio is great (and they have nifty sample tins so you can try before committing too much cashwise.

I'm not a big tea-drinker, but people say good things about Upton Tea
http://www.uptontea.com/

I bought some Darjeeling and some Sencha from Tea Gschwender recently:
http://www.teamerchants.com/US/en/Homepage.TG The company is based in East Frisia where people tend to drink tea with milk, so you might check out their recommendations. I used to usually drink black teas with milk, but I've been enjoying the Darjeeling straight up. I think you might want a heavier-bodied tea for milk, though.

My SO swears by the Taiwanese company Ten Ren http://www.tentea.com/
but he doesn't drink much black tea and never uses milk.

San Francisco Herb Co. has loose tea by the pound at great prices.

I just searched for the word "organic" on that site, and only one entry came up. And it was non-certified organic, at that. Oh, well.

The only thing that came up when I searched on organic was a green tea.

Porto Rico Roasting Company is good.

I don't drink tea very often (generally just not a hot-drink person), plain tea pretty much only if iced, and never with milk, so ignore anything I say here :-), but still, here is something cool I recently got.

I *swear* by Upton Tea. In the dim past of the mid 90's, i was able to call and have them help me place an order when i didn't have a catalog handy, They referenced my previous orders and were able to suggest new teas. While the web has supplanted that now, i suspect you could send this query to them and have them suggest some teas.

Or you could go to the list of breakfast blends and select a bunch of $1 samples:
http://uptontea.com/shopcart/catalog.asp?parent=Teas%3EMiscellaneous%3EBlends&category=Breakfast&sortMethod=&begin=0

Roasted rice teas from Japan are in this section
http://uptontea.com/shopcart/catalog.asp?begin=0&parent=Teas%3EGreen%3EJapan&category=Other

I like that they have some organic teas. Their "we choose" shipping has always satisfied me to my Presidio and Mountain View addresses.

HTH!

I buy a lot of Ahmad Tea Company tea from online sellers. Amazon is a reliable source for it, but you can find it from other retailers sometimes at lower prices.

I usually drink their Kalami Assam tea, but that might not be as strong as you like. My daughter Amanda likes strong black tea and she likes their Ceylon OPA tea. You can find it using Google marketplace, as well as at Amazon.

I'm fond of the genmai chai from Republic of Tea, it's their "Tea of Inquiry".

For a strong black tea that can stand up to milk, it's hard to surpass Red Rose tea. I have no idea how you'd get it other than to have a Canadian ship some to you. I'd offer you some of my stash, but I'm down to my last couple of bags.

I buy from Upton Tea, too, but I mostly buy Darjeeling. I can't imagine putting milk in tea!

I haven't tried Coy o Teas yet, but thought I should mention them. :)

I love teas though I'm not fond of loose teas. My Yarn Angel, who is also my Tea Angel, has bought tea for me from Stash Teas. Have you checked there?

nex0s just tried out serendipiTEA ( http://www.serendipitea.com/ ) and Lupicia ( http://www.lupiciausa.com/ ) and was raving about both of them. Enough to tempt me to order (and I do *not* need any more tea!).

I order tea from: http://www.keepingstillmountain.com/index.html

equo.com - fair-traded and organic. Their Chai Masala is amazing, delicious with milk or cream. I don't know if they have loose tea or not.