a base 8 day ticket is $252
that's just entrance into one theme park per day.
if you want to park hop (enter more than one theme park per day) it will be $306 for 8 days
if you want a ticket that will let you visit the waterparks and disneyquest, but without park hopping it will cost you $306 for 8 days
if you want to park hop and visit the waterparks and disneyquest it will cost you $360 for 8 days...
if you buy in the UK, the 14 day ultimate ticket will cost you approximately £230 (depending where you buy it)
the 7 day ticket will cost the same and it has less flexibility, so the 14 day is the better ticket...
anyway, that's about $370....
so for about $370, you get unlimited entrance into all the disney theme parks, waterparks and disneyquest....as many entrances as you want each day for your entire stay...(since you'll be there 9 nights, so theoretically, you might want to enter a park on 10 days)..
the tickets offered in the US are not as flexible as the UK offered tickets...
if you buy the parkhopping, waterparks and more ticket, you get unlimited access to the 4 theme parks (MK, epcot, DHS and AK), but only a limited number of entrances to the waterparks and disneyquest...
however, the limited number is often all anybody wants......
so it seems you're probably better off with buying the tickets in the US....
although, personally, i prefer the UK 14 day flexible, since we like to be able to pop into the waterparks for an hour in the afternoon and then pop into disneyquest for an hour...you can't do that with an american ticket since you only have so many entrances to the extra stuff...
(i don't think i'm explaining myself very well)..
but most people don't need all that flexibility..... they're good with the US magic your way tickets...
by the way, the US ticket prices can be found here:
http://www.wdwinfo.com/wdwinfo/tickets.htm#tickettypes