I go through phases of dreaming about a lotto win and new scope, and being very happy with what I have. I've just come out of a dream phase yesterday, thanks for bringing this up again guy's.
I am surprised how if you're happy to go the big bucks, how many options are out there of 20" and larger. I'm not sure how these guy's make any money with so many competitors. For example, if I won enough lotto money my short list would include:
http://www.opticalguidancesystems.com/
http://www.rcopticalsystems.com/
http://www.meade.com/maxmount/index.html
http://www.anssentechnologies.com.au/
If I were to actually have the money, it would take some serious investigation to actually work out what is the best option. At this sort of end of the spectrum I think the equipment would really need to be focussed towards a specific goal, it's not like a 8" SCT which is more a "one size fits all" uses situation.
The few linked to above have interesting differences, some start and I find it not so easy to compare them - PE for example varies surprisingly between them, as does focal length for the same aperture.
I'd also allow about 1/3 the budget for additional instruments (CCD's, instrument rotator, spectrograph, guide scopes, etc).
Of course before all that is contemplated, the home loan would need to be paid off, and that would take a serious chunk of the lotto winnings!
Also I have to admit that only a small proportion of the money would go on equipment, the rest would be kept to allow time to use the equipment. I already have more telescope than I can use in the spare time I have, it wouldn't get any better with one of these things! I'd make sure I keep enough money to cut back working to 4/days week or something, to get an extra bit of spare time to use the stuff.
Roger.