If you like Tung Ting, you obviously lean more towards the lesser oxidized types of
Oolongs (opposite of the wuyi styles), but just to be clear, there a some types like
these that are "unrolled" unlike tung ting/ti kuan yin oolongs. Adagio's own Oolongs #40 is a good example, and though their ti kuan yin is basic, still very good.
Some good places to try some Oolongs are Teaspring, Red Blossom Tea, and Special Teas, in my experience
Some other sites:
Teaspring (good selection of a wide variety of Oolongs):
-Dan Cong - any of the types of Dan Cong, though my least favorite was the Song Zhong.
-Huang Gin Gui - very nice
-Yong Chun Fo Shou - though I've not tried this one yet, I want to
Red Blossom (also has a great selection):
Easily stated, just stay out of the Wuyi section in your case, unless you someday discover you like Wuyi-style Oolongs. Some of the Oolongs on this site are incredible, but also incredibly expensive.
It's hard to make any recommendations here, since all of them are great...so I guess it just comes down to pricing and what you can afford to sample, and I do suggest sampling. I'd say their best deal is the Eastern Beauty, which I've seen sold elsewhere for much more money, unless I've just ran into some sites with bad high pricing. And I can recommend the Imperial Mist if you want to try something more high end without paying as much for the Li Shan's, for example (Heaven Mist might be okay, too...haven't tried it). They have a Ti Kuan Yin - Monkey Picked for a very low price compared to what I've normally seen, too...though I'm not sure why this is.
Also, try a milk/silk Oolong is you haven't yet. It's an interesting experience.
Special Teas :
I'd recommend Special Teas more for sampling than anything else. They have good prices on samples, and a decent selection. I've not been disapointed by them.
A few unique items:
-Hairy Crab Oolong - nice, floral and peach-like
-Zhongshan Baiye - haven't tried it, but I hear it's good. A bit more highly oxidized, I think.
- Himalayan Oolong - this is a new addition and I look forward to trying it. It appears to look like a "fancy" Formosa style oolong (like #40)
And a curveball suggestion,
Silver Tips has a Darjeeling Oolong, from the Makaibari Estate. I've tried it and liked it very much, and at a modest price.
Anyways...there might be more places to order from that are just as good, but these sites are the ones I personally have experience with (good experiences).