I think the two most popular blog sites seem to be Xanga and LiveJournal because they offer a bunch of services for free.

I guess they do have their own pluses. If you're not too web savvy, Xanga's the way to go. It's easier to customize your journal there, and you can also add music. With LiveJournal, you can customize your page however you like, but it's more difficult. But--they do offer a bunch of different styles you can choose from to create your page. My page was done with css style codes (that I didn't do, obviously!). I guess Xanga's more user friendly.

I like LiveJournal better because you can make posts public, private (for your eyes only), and friends only. And within those you save as friends, you can also filter posts so that all but say one or two friends to see your posts. To my knowledge Xanga doesn't allow private or friends only postings.

The communities on Xanga are also easier to navigate than Xanga (they have blogrings). But Xanga also offers some storage space for pictures.

Both sites offer premium services for a fee...you get extra storage space and more user icons.

But as far as reliability goes, LJ goes down often (more than GC!). It's not for that long though, as they have people working around the clock to fix minor glitches here and there. To my knowledge, Xanga's only been offline once in the past few months.

I chose LJ mainly because I knew that a lot of my friends were already on it, so it was easier to make posts friends only.

Hope that helps!