I am slightly amazed that people would give up losing weight, or even intentionally re-gain what they've lost, just because of excess skin!
Surely the single most important thing is to be healthy? Excess skin can't be nice, but as purple_star says, it isn't going to kill you!
If it is something that really worries you ColJack, it might be worth thinking about how you can minimise it - and you can - by losing weight slowly, so the skin has more of a chance to keep up with the losses, and replacing the fat with lean muscle through exercise, which gives the skin something to 'stick' to. Losing weight quickly is all well and good, especially if you can do it without exercise... but its not the best way for your body, let alone your skin!