TBH you'll need a very good wireless router indeed to get the full 50Mbit all over your house.
I am currently looking at the Linksys WRT610N. Overclockers.co.uk have an excellent deal on at the moment - and £20 cashback if bought before end of April:
http://www.overclockers.co.uk/showpr...source=froogle
The best feature I believe is that you can have your N devices running on the 5GHz spectrum and G devices running on the 2.4GHz spectrum. Stops the G devices slowing down the N devices and also 5GHz is in scarce use so plenty of spare room for your signal to spread it's legs
Review I read shows over 100Mbit/sec (just) performance on the Wireless-N 50 feet away!