I'd also consider the new galaxy nexus. I know the screen is smaller but it's still a behemoth (hardware- and screensize- wise) with a 4.65'' 720p display.
Regarding the hackability you're better off checking the phones' threads here on xda to get yourself a quick idea of how things are going to evolve. My prediction? the galaxy nexus will be modded, haxxored & supported beyond imagination.
If you think about it, the streak modding community is unfortunately too small. As it has been said over and over many times, the point is not that dj steve, fards and all the other few great guys are not "good enough", but the strength of the hacking/ROM community is in the BIG numbers, and you can bet your house the galaxy nexus will deliver.
Not sure about the galaxy note though. As the streak, its size makes it a niche device, and although sammy is supporting his product way better than dell (at least with proper advertising, clear upgrade schedules etc) i guess the big numbers of the above will not come to the note.
therefore, for my next phone I'm willing to sacrifice a small amount of screen real estate in favor of an incredibly bigger community, with all the benefits/ major geekery that come with it. I'll surely keep an eye on the note though, since it will take a while before I change device. Who knows, I could be proved wrong..
3210 (still alive and well) > 7110 (sold) > 6600 (sold) > 6600 (sold) > n70 (still alive and well) > hd (sold) > streak (alive but broken) + xe (perfect)