I have owned Sharp Aquos and Sony Bravia TVs, and can highly recommend either brand. LCDs are great screens, and won't burn in under almost any circumstance, while plasmas have insane contrast and reproduce black very well. As mentioned earlier though, they do have the potential to burn in. Only other thing is, many LCDs are LED-backlit, meaning their backlights are very energy-efficient and will last a hell of a lot longer than traditional cold cathodes. As far as *I* know, LED-LCD screens have plasmas very well beat in life expectancy.
On a side note, I think the 120/240Hz displays are a bunch of horseshit. 60Hz have served me well...