SAMSUNG
One of the most popular of the current flat screen brands.
A large range of these sets suffer from capacitor issues which can result in the corruption of the eeprom ic on the mainboard if left unchecked.
Symptons generally begin with the set taking longer to start up.Red light blinking,relay clicking then possibly switching on after 10 minutes or so.This time gap will increase until eventually not switching on at all.

LG
Another increasingly popular brand in recent times.
These LCD's can suffer from a similar problem to the samsungs where the red light may not turn to flashing green straight away and eventually no red light or red light goes out but no green,no matter how long you wait.
Another common,although less common problem can be a flickering pulsating backlight.
Another popular one on certain models can be crackling audio,loss of hdmi and loss of freeview channels.

Acoustic solutions,wharfedale,hitachi,sanyo,vestel.
A very common problem with the above mentioned LCD's can be when switching on from standby,the (usually) blue LED goes out but nothing else happens.

A typical repair charge for the faults mentioned would usually be in the £65-£75 price bracket.Obviously this wouldn't apply to every case and the television would need to be inspected first but if your television has any of the above symptons then it is more than likely to be well worth repairing.

Together we can do our bit for the environment and reduce landfill with repaired televisions happily carrying out their role for a few more years.