What is it about these guitars that everyone wants? I can't see it?
I can't answer for everyone, but for me it's a combination of tone, build quality, playability and aesthetics. I know they have a bit of a reputation for too much 'bling', but every one I've ever picked up has impressed me as a player's guitar first and foremost.
I don't go for the very gaudy tops with gold hardware - they're not my bag, but I think guitars like the SC245 I have strike a pretty decent balance between pretty and being workhorse instruments.
I also realise they come in for some criticism for being expensive (sometimes prohibitively so), but a decent Gibson LP isn't cheap. I looked at a bunch of LPs as well, and the only one I played that even came close for me in terms of sound and playability was only £50 cheaper, and had finishing flaws and the upper strap button misaligned. I'm not saying all Gibsons are like that, but the only one that felt 'right' for me had flaws that I was not willing to accept on a £2,000 guitar.