suggest me a nice HDTV

i want to buy a nice TV. here are some of the requirements:-

full hd reqd
usb port for playing movies
screen size 42"-56" or even more
budget around 40-65k

i would also prefer if it has dlna/upnp feature. though not absolute requirement

is led worth the extra money?
are the lesser known brands worth buying over say sony,samsung for the money savings?
also using the usb port can i connect my 500 gb harddisk and can they usually play mkv or other hd files?

ALSO in Mumbai is alfa good place to buy tv and which other shops are good?