Every tv can be controlled via IR remotes and devices like GlobalCache iTach IP2IR or GC-100.
Also LCD/LED tv can be controlled via serial rs232 and hdmi port. HDMI way is tricky and expensive so you are left with only using IR or RS232.
If you are buying new TV I urge you to buy LG tv because they have RS232 ports and most LG tv's have cheaper models that can be unlocked to have same high end features as much more expensive models (just google for lg firmware hacks).
There is also nice WIKI page for controlling LG tv's via serial RS232:
Any comments and further suggestions are welcome.