Panasonic, Sony and Samsung are the best bets
If buying a Sony, and maybe a Samsung, get an extended warranty – Sony often have a 5 year on offer, and John Lewis do a 5 year on all their tvs.
The menus on my Sony are playing up badly, and the Samsung that I recommended to my sister lost a big chunck of screen just after it finished it’s warranty.
Sony’s are not universally best bets either – when I bought mine (which was one of the best around at the time for moving images) the colors were wrong and needed a trip into the service menu to fix them, and the 40inch version of the same set had shocking ghosting/clouding on moving images.
I would go for a Panasonic – I wouldn’t bother looking for youtube/etc compatibility but just use my PC plugged into an HDMI slot.
If the TV works with youtube now, it might not later when a new version of the various technologies like flash used get updated, whereas it is easy to keep your laptop up to date.