I don't think I would think twice about that question. I would never pay for Gmail. No matter how good it is. There are other free 1 Gig email services, like Walla (
http://www.walla.com). And while Gmail might be much better, I think there will always be free email services, so I don't plan on paying for any email services.
Yahoo is now offering 100MB of storage, and Hotmail is planning on offering 250MB of space.
While I do think Gmail is great, and now the best mail service avalible, I wouldn't pay for it. Mostly because I'm too cheap
-Julien