[Jason.]

BB5, BB6, BB7, and BB8.
All had fantastic launches.

The BB5 launch at the time was amazing. After the last ever Friends. I remember it launched at 10, too. I just loved the electric atmosphere.
You knew it was going to be great, once all the housemates walked in.
The house tour was funny too.

BB6, and BB7 are similar, but they were great.
I think BB7 edges it though, as it looked really fun.

BB8 was a good launch, too. Although the launch twist wasn't great. But the housemates VT's, and house tour were good.
It had a good atmosphere.
Also, the exterior of the house was different, so it felt fresh.

BB9 was okay. The VT's that year were great. But it seemed different. I think that was when the crowd began to get smaller.

BB10 was shut. Flattest launch ever. One dimensional.

BB11 was okay, as it was different.
It felt like an event, and it was exciting at the time, because it was the last one.

BB12's was crap.
Don't remember much of BB13's.

BB14's launch was great. Felt like a Channel 4 launch. As did BB15.
I think BB14 edges it though, as the BB15 launch had a ruthless "Hunger Games" feel to it.

CBB4 and CBB13 launches were amazing.

Best

BB6 / BB7
BB5
BB8
BB14
BB9
BB15
BB11
BB13
BB12
BB10

Worst