It really depends on if you're going for quality or quantity. While I have not personally seen the 70" LE632, I have seen both the 60 and 80-inch variants in our store, as well as the 70" 732 and 735.
Since it seems like you already have a projector for critical viewing, the superior image quality from the ST30 may be worth less to you than the extra five inches of the Sharp. Since you say, however, that it will mainly be used for watching hd tv shows, I have found that with less than perfect sources, i.e. anything other than a Blu-Ray, the Sharps are noisier and show more artifacts than most LED TVs, let alone a plasma. Panasonic plasmas will show a more pleasing image on a compressed 720p/1080i source due the inherently softer image of a plasma. The Sharps noisier image is probably partly due to the gigantic size of the panel, and I'd assume less than stellar image processing that Sharp uses in the low-to-mid tier sets. When fed a good source the Sharp actually looks pretty darn good, not great, mind you, but pretty good. My only complaint is that they do not handle motion very well; motion handling is improved on the LE735.
The plasma will have basically perfect motion handling, viewing angle, uniformity (although the big Sharps are pretty good about this), and better color than the LED. The LED will be brighter and five inches bigger. I know which I would choose, but ask yourself which aspect you value more.
ht Panasonic 60" ZT60, Monitor Audio: Silver RX6, RX Centre, RX1; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D, Panamax M-5100PM
2ch Sony 32" W650A, Sonus faber Toy Monitor, REL T3, Marantz PM8004, Sony BDP-S1000ES, JVC T-X3 tuner, Apple TV, Peachtree Audio DAC•iT, Panamax MR4300
pc Monitor Audio Radius 90HD, Audioengine D1, FiiO A1
+ Sony 65" XBRX850B, Sony BDP-S5100