I

the concert in Japan the most which is this one,
Teresa Teng Last Concert at NHK HallThe reason: I think all the technique during her hey day outside Japan, likely in 60s and 70s, was not up to the snuff. Sound engineer in Japan really caught the magic of her voice, even this is a live performance. IMHO, music was rearranged to actually sound much better than original version (see below). With most rearrangement of the music, you may long for the original version no matter how good the rearrangement is. However, for this one, I'm more satisfied with the rearrangement. If you ask me now, I wouldn't bother to get the original version for comparison if I could get the version with Japanese rearrangement of the music.
To me, this concert is rather mesmerizing and I was really blown away with the first llistening. This, to me, takes Teresa Teng music to the new height and I got hooked because of this album. Of course, there were certain dub/changes after production on the live recording but I think she sounds the best for most of her recording in Japan. I highly recommend for this one if you could find it.
This version was first issued in laserdisc format which, I believe, was used as a test disc for various AV system in that era. I still have LD version of this one hiding somewhere in my mom place. It was also issued in DVD too but the review seemed to indicate a rather disappointment. I bought the two disc version of this CD from Japan a while ago. Quite pricey though! It seemed to be a norm for anything to do with Japan, ie Japanese pressing.
http://global.yesasia.com/en/PrdDept.aspx/pid-1003846460/code-c/section-music/I think this 15th Anniversary is a good introduction to her music. I used to 'not'

this kind of music so much until I have the above Japanese version. Now, I find the collection, mostly original music outside Japan era, listenable. It reminds me of music that was sang in Chinese style night club in Bangkok. This one seemed to be the most affordable of all. This is the one that Khun ไท… talked about.
I also have this one,
http://www.amazon.co.jp/exec/obidos/ASIN/B00005FOTN/ref=pd_sr_ec_ir_m/249-1937388-8531541, in XRCD format. I felt so so with the CD but this seemed to be a good album or something in that they issue an audiophile grade LP version not too long ago.
I think Khun MDF should be able to add much more for this name.