see iv had alot of the high end phones 9900 - iphone 4 - etc but i sold my phone to buy a crosser a while back and just want another phone i will probably use it mostly for texting bbm or whatsapp. facebook - twitter - browsing and watching a bit of twitch tv ( justin tv)
however i do like to customise my phone screen like the way it looks etc as i get bored very easily
For everything you describe I would go with the blackberry as windows phone 7 is not really customisable at all. Unless you can manage to jailbreak which at the moment I understand is not easy to find one as I tried to find a JB for my Trophy to no avail. only bonus would be the bigger screen on the Nokia and exclusivity.
The only other thing is
I did not find battery life that good with my trophy but obviously cannot comment on the Nokia
You might want to pick up a used device until BB10 and windows 8 is released..I have both windows and blackberry and its a tough choice for me. Until I see BB10 I am leaning towards windows mobile. One thing blackberry has over any platform is the notifications which no other carrier has perfected like blackberry.
see iv had alot of the high end phones 9900 - iphone 4 - etc but i sold my phone to buy a crosser a while back and just want another phone i will probably use it mostly for texting bbm or whatsapp. facebook - twitter - browsing and watching a bit of twitch tv ( justin tv)
however i do like to customise my phone screen like the way it looks etc as i get bored very easily
My suggestion would be to buy neither. Both BB OS 7 and WP7.5 are End Of Life. If you get bored easily, you should pick a phone likely to get some OS updates. If you like to customize your home screen that would suggest Android.