I could be mistaken, but I think the samsung 61f model has a reflective screen, which could be a serious consideration based on your lighting situation.
The 72U is a newer model than the 64U, but Sharp's newest models are 92U, and even that is due to be updated soon since it has been out for about a year.
Although much more money, the Samsung 71F series is the best LCD I have seen, I even like it more than the Sony XBR4 - although I think Samsung makes the panels for Sony.
The Samsung Plasmas are also pretty decent, the 5084 is one I was considering, but I would only get a plasma if you have good control over lighting.