I want skype because a lot of my friends use it. It is the main messaging service I use. (together with an IRC channel and a little bit Whats-app).

If you really want "bigger and better" why use an old N9 ??
It is hard to deny that other smartphones are bigger and at least better from a pure hardware point of view.

The fact that an online service is monitored by the NSA doesn't really make the service less secure than ordinary phone-calls, and doesn't make the N9 itself less secure.
The main security concern for most people in mobile phones is the possibility of identity theft when your phone is stolen, or when an installed application isn't what the user thought (malware).

I'm not entirely sure about all the security features in the N9, but the N900 for example is really not secure by default. Wifi, account and online password can be recovered from a stolen N900 rather easily, and applications aren't sandboxed by default.

It is very difficult for a consumer to judge the security of mobile phones. My impression is that security actually is a high priority for both iOS and Android, but I have doubts about the security in the N9 and Windows Phone. My impression is that it is more of an afterthought in these devices (but practically also less of an issue because of the smaller user-base)