TVs usually don't have headphone ports. Getting such a large TV and not even having a basic sound setup is asinine. Buy yourself a receiver for now. Any receiver will do. Not a headphone amplifier, because the receiver will be more versatile and will drive your headphones fine. Like this:
http://london.craigslist.co.uk/ele/2061137841.html
Buy a 6.3mm to 3.5mm adapter, maybe a cable extension, and now you have a way to use headphones with your TV. Plus, in the near future, grab yourself something like these (maybe search Craigslist after Christmas, when people are getting rid of stuff after they receive gifts):
http://www.amazon.co.uk/Sony-SSB1000-2-Way-Bookshelf-Speaker/dp/B000OQ3TGW/ref=pd_cp_ce_1
Even though they are low-end relative to what's out there, they are cheap, and they are about 5 times better than the current sound you are getting. I gave a friend of mine an OLDDD receiver I had for his Sony 42" plasma. He used analog, stereo RCA connectors to connect to his TV, got only speakers similar to what I posted above, and even with only 2 bookshelfs, the difference was night and day. This way, you will be able to use your headphones when gaming/when you're alone, and you will have decent sound for when you have company over. In the future, you can upgrade this system piece-wise. Get yourself a subwoofer, then get yourself a center channel speaker once you find one on sale, then get yourself more serious front surround speakers, and move those Sony to the back. Voila, you now have a 5.1 surround system.