I'd recommend a paid service over a free one for sure. I use http://www.smugmug.com , which costs $40/year. It has outlasted a LOT of free services, including Kodaks, Adobes, and others. I would bet on Yahoo's service staying around for long, though it HAS done better than most.

The nice thing is that with Smugmug you get UNLIMITED downloads.

Flickr does allow folks to pay for unlimited downloads though, so that might be why they've lasted longer than most free sites.