The New York Times began offering a paid subscription last month. Basically anyone can read up to 20 articles a month for free. After that you have to pay up or wait for the new month to kick in. I never really kept track but I was fairly sure I hit my limit well before the end of a calendar month. What surprised me was when I signed up (99 cents for the first month, $15 thereafter), when I signed up I did not feel like I had just made a NPR donation or a relief for Japan, Haiti, Kathrina or tornado alley contribution. Fifteen dollars a month is a deal.
I read the NYT often. I hunt around in the archives for research, I get three of their teaser email newsletters and click links often for the full stories or editorials. I nearly religiously read the Sunday Review of Books usually on Thursday when it comes out online. I also read the online version of Atlantic (Monthly) still free, it would be a more difficult decision to pay for it; I really prefer magazines in hard copy, particularly the longer pieces. The Economist also gets a cyber-passthru each week but again a subscription might have to be for the hands-on edition. I read both the Atlantic and the Economist at the Berkeley Public Library, along with several other research oriented periodicals; usually on a very hot or rainy mid-week afternoon.
I also am not sure about magazines on eReaders. Books yes, but there is more to a good magazine than the words. The illustrations and the New Yorker cartoons don't translate so well to the digital screen.
Ah what literary times of choice and bounty we dwell within.