I also never had a LED display (only entered the Mac world this past may), but my TB display doesn't really get warm at all. I suppose it might depend on what is attached to the Magsafe connector, but when just using my 13" Macbook Pro for normal everyday tasks it doesn't seem to load the TBD's power supply enough to create any significant amount of waste heat...
If I had a 15 or 17 inch MBP and ran something that used the discrete graphics processor and loaded all four CPU cores maybe I'd notice a more significant heat output, but alas.