Hi Eric,
I'm by no means a handplane expert, but it seems that I'm in a similar situation as you - pretty much a power tool user, but moving towards using hand tools more often or as needed. I've grown my handplane collection over the last 12-18 months from about 1 (a POS block plane that I found in my garage when I moved in) to, let's see, 16!!! and I might've missed one or two. Anyway, here's my first tip, go to
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and check out their hand tool message board. There are a ton of great contributors over there that can offer you a LOT more help than I can. Do you read Popular Woodworking? Well, Christopher Schwartz, one of their editors, posts there all the time and he's answered my questions several times. Rob Lee from Lee Valley, etc. etc. all seem to be over there.
Anyway, aside from that, which is probably the best information I have for you, I'd say you're thinking about this the right way. For large boards (as well as small ones, depending on what you want to do), and assuming you want to go from rough to ready, you probably want a scrub plane, a jointer, probably a jack plane and then a smoother. There are many ways to skin this cat, though, and I won't pretend to know the best way.
As for the $$ issue, you'll probably be surprised (well, I was at least) that $900 won't buy you as many planes as you'd think - at least not if you buy new planes from somewhere like Lie-Nielsen. For example, using their latest catalogue, to buy the above planes (no. 7, 5, 4 and scrub) would run you $1145 + shipping. So, you have to think that one over.
What I did (and many others out there) was to try and find old Stanley planes that were in good and usable shape. I found several on ebay, and a couple local. I did buy a few new planes, though, so I have a pretty good mix. It probably isn't surprising that the brand new Lie-Nielsen planes work wonderfully and perfectly right out of the box (save a little honing perhaps of the irons). The Stanley planes I bought, however, work great too, just after a bit more tweaking and elbow grease.
The other issue you brought up that I think is important, is that if you want to work difficult woods, you might need some different planes, or at least extra blades at steeper angles. So, you never seem to have enough planes. The myth isn't a myth. Neither is the one about how satisfying it is to use a good hand plane.
So, anyway, I'm not sure if this information is very helpful or useful - pretty much stating the obvious - but, my point is mainly that you should take all your needs/desires into account and then look at all the sources available and follow your gut. I know I'll have a lot more pleasure teaching my son (age 10.5 months so I have time to actually learn how to use all these planes hehe) how to get a wispy shaving from a well-tuned plane than I will showing him how to use a power planer or jointer and not lose his fingers.
Mike