Islamabad is a great city (at least by Pakistani standards, which is not quite the same thing!). It's green, relatively calm and quiet, and pretty tidy. The Marriott is nice although I have to say I prefer the Serena.

What to do...Monal is nice, a restaurant up in the hills overlooking the city. Des Pardes is also good. Lok Virsa is good for shopping and for learning more about Pakistani heritage. If you want coffee head for Kohsar Market, Mocca Cafe and Gloria Jeans are both good. There's a new mall which just opened, Centaurus, which is pretty impressive.

Security-wise it's really not as bad as you read. Avoid the area known as Aabpara, especially on Friday afternoons, and don't go around taking photos of things in public. Otherwise just chat to people, enjoy their hospitality, learn more about their lives...you'll find Pakistanis to be almost universally charming.

Context: I've been living in Rawalpindi for two years so I have seen quite a lot of the twin cities. It's not a perfect country by any means but it's certainly not as bad as the media makes it out to be!