As a long time Pentax user, I soon learnt to stop looking across the pond and love the one I'm with so to speak!!
5FPS for weddings? What kind of stuff are you doing that needs that? I've never noticed that being a limitation for the weddings and events that I've done the last year. I'd be interested to know.
Weather sealing however, that's another story! With the summer weather we've had this year, a couple of times I've been out in the pouring rain whilst the bridal party have been safely ensconsed within the church porch, and weather sealing was much for useful than a couple of extra FPS.
Regards ISO, the big numbers we're starting to see only make sense if the photographs are useable. My K20d can do 6400, but you wouldn't use them (apart from in some kind of abstract way!), and I certainly wouldn't dream of including them in clients portfolios.
I've shot in some very dim venues this year, and again I'd say lenses come to the fore here. I've shot on the K20d at 400 iso with a Pentax 16-50 f2.8, and the results have been great. I've heard that the D3 is in a different league regarding ISO, but it is in a different league price wise too.
I know it sounds like I'm berating you for being disappointed at the 5dII in comparison to the Nikon competition, I suppose I'm just trying to help get it into perspective.