The Zombie Stack Exchanges That Just Won't Die
Many external links to Wikipedia are now dead links. I know not to trust Yahoo News, for example, since its links become dead links quite rapidly.
InquilineKea
You should generally avoid commercial sites. They have a tendency to close their articles for subscribers only, so is with the New York Times. Even if some portal have free archive now, he can change that policy in future. There's nothing more annoying than clicking in the link and having the screen requiring to pay. This can even make your visitors think your website is commercial and leave it for all.
The best way to refer to newspaper articles is to cite everything crucial, and provide the source as bookmark, with optional link (but the number of physical newspaper being more important, it is more likely to survive than link).
Not sure if this is an option in your context, but the only way to make sure URLs will not break and will still deliver the same contents in the years to come is to archive them. There is a non-commercial, free service that does just that: WebCite. You could then provide two links: one to the original source, and one to the archive copy at WebCite.
If providing two links or just archive links is not an option, I would second @lechlukasz in suggesting that non-commercial news websites are more likely not to move contents behind a paywall. Perhaps WikiNews is a safe bet for stable news links, being an official WikiMedia project just like Wikipedia.