This is the larger flowered plant. The smaller flowered one is labeled Euphorbia milli. Which is this?

Euphorbia milii var. splendens

The so called Thai Giants ( / larger plant and larger bracts) are properly called Euphorbia x lomi.
(First two letters of: lophogona x milii)
I would like to see the whole plant, but I think that is what you have here.

Thanks. I did not take the full plant picture. Now that plant is out of the house.... under neglect, outside the compound wall. I faced difficulty in handling the areas around it and also the pot it was in. I am not comfortable with thorns. I dug a hole outside the gate and put it in there -it is surviving there and flowers sparingly. I do take some effort to water it once or twice a week in summer months. I can take the picture sometime.. so let's wait. I also had the smaller one which had produced many shoots and was thriving.... same problem with thorns and I did not repot it. Just disposed it off... I miss the flowers, but it is ok as it had thorns. I did have the yellow one too.

No problem. I am pretty sure you have the E. X lomi. To pinpoint any cultivar however might be a little more difficult or surely impossible, there are so many out there.
I have now restricted myself to only one plant each of white, red and a gigantic plant with pink blooms. I had way too many....
We saw these plants in Thailand everywhere, growing in many gardens in large pots in full sun. They can take a lot water and fertilizer and so bloom beautifully under those conditions.

http://toptropicals.com/catalo...
the spottiness of the flower causes the virus - Euphorbia ringspot

regarding Toptropical - the milii indicates tiny blooms/bracts.The friendly guys at that nursery are not exactly the gospel regarding the id of their plants.
Dinu talks about a larger size bloom here, no?

and I don't see any ring shaped chlorotic spots on the leaves of his plant indicating any virus.
for your reading pleasure
http://www.academia.edu/454418...

the picture is clearly visible bright patches on the leaves

Stefan, I am not sure we are talking about the same thing here.
Please, don't mind me, but I think I bow out here, I do hope still gracefully.

Dinu, I found the cultivar Siraya that looks similar to yours.

Thanks zencat.. I'll be checking on that Siraya...... I'll revisit this thread...... just for the time being, a poor photo of the plant I wrote I moved out of the compound. Will get a better one soon.
I've kept it there as if to keep watch on the dirt that irresponsible people throw in the rain gutter, which becomes an unsightly and horrible mess!

http://floramalaga.blogspot.in... Mine is like the second picture in this blog.

Will come again to this thread.. till then this new photo of the plant outside compound. Doing well and showing a bloom too!

Still pretty!

i found this very informative article with names of cultivars and care tips.
http://wanapluk.com/article.ph...
they give a 'color description' for each cultivar - but it's not so easy to visualize.
i took this pic on the streets of South Beach, FL - looks just like OP's.
could this be :
‘Pink Christmas’: cream, becoming suffused with pale pink & reddish streaks?

you can see a list of varieties that they sell - all thai names though
http://www.wanapluk.com/plant-...
'Boon Sangsom' looks pretty close.

skylark, yours looks like x lomi to me.

i think so, it's a giant thai variety for sure - the link i posted above said:
many of the Thai hybrids have more handsome foliage that is larger & a brighter green.

In Thailand these plants are known as “poysean” (Chinese for 8 saints) & are regarded as bringing good

luck. Their exact lineage is uncertain, & the formal botanical name E. x lomi Poysean Group has been

proposed for them.