what is the ideal setup in terms of amount of circuits for a HT setup with say a 60in plasma, outlaw 7700 amp and dvd player.

Should i install a separate circuit for the TV (15amp) and a separate circuit for the audio 15amp or 20 amp?

What is the ideal way to do it or it doesn't really matter?

It definitely matters how the circuit is designed. I am pondering the same questions and I plan on providing 4-20 amp circuits for my HT setup. I will likely only use one or two at a time but I want the flexibility. Each 20 amp circuit provides approximately 2000 watts of available power at the receptacle with a little headroom for peak power. I have a power conditioner and all of my equipment is plugged into it for two major reasons:
1) All of the equipment shares a common ground to minimize ground loop problems
2) All of the equipment is protected by the conditioner.

The conditioner has a voltage and wattage output monitor so I know how much current is being drawn by the system. With everything on at high output levels it stays less than a thousand watts typically which is 8-9 amps. Even with all my equipment at its rated output it would still stay less than a 20 amp circuit can supply. If you install your own circuits make sure they share a good common ground on all circuits to avoid the ground loop issues. That includes your cable/satellite TV box and any antennas you may have. I will likely install some sort of dedicated protected circuit for just the HT room when I construct it.

should i try to put the audio equipment on one 20 amp circuit and the video (like Plasma TV and or DVD) on other separate circuit to avoid any picture quality issues or doesn't matter?

I have all of mine set up right now on one circuit with no issues. If you do use two circuits make sure thay share a GOOD common ground. If the grounds are different even by a little bit you will have a ground loop present. Depending on your equipment the audio is likely to draw a lot more power at full output but it rarely runs there. If you are concerned that the Video will be adversely affected by a large power draw on the audio side then go to separate circuits from 2 different breakers in your power panel.

I use a single dedicated 20 amp circuit for my audio and video equipment and there has never been an issue with the amount of AC power. However my subwoofer is off a 15 amp circuit that predated my remodel and family room HT. I couldn't locate the sub near the 20 amp outlets due to room constraints. I ended up with a ground loop caused by the different ground used for the cable box and induced a hum in the sub. If I had it to do again I'd add an outlet for the sub from the 20amp circuit. I don't know if that would have solved the ground loop caused by the cable box but it might have.