As for me, I started developping my own organ sounds on my XP not long ago because I found that the preset sounds were ... well, not inconvenient, but didn't quite match my idea of cool rotary sounds. I don't have much money left to buy JV/XP expansions (it would be hard to decide whether to take the cool "Vintage" or cool "Organ" one anyway) and I'm not experienced (let alone own a patch creator) either, so now I'm in the process of experimenting with internal waveforms and so far I have tried to design a patch featuring more mean, less "nice" and more "rocking" leslie&hammond sound. I don't know if anybody except me would appreciate it, but personally I think that without software you might still "design" patches if you know what you're looking for. On the other hand I think that some instrumental sounds really suck because they sound like pads even if they're entitled "lead" or so. So far I haven't found out how to improve them by toying around with my TVA...