I have been using easy urpmi (
http://easyurpmi.zarb.org/) for all of my updates and such. But it seems likes every few weeks, I need to re-enter new sources for main, updates, and contrib.
If I haven't upgraded anything in a while, the usual problem is that the md5 checksums don't match. This causes a lot of havoc, because they are still downloaded, but now in cache. The installer programs then never try to re-download them, and I get the same md5 errors. Sometimes, I get errors that the servers are misconfigured, or it cannot reach the file.
I can go to the above website and get a different mirror location, but to be honest this is a pain. Are there any mirrors that are reliable? (North America) Or, is this just behavior I can expect. It's still much, much easier than Windows(tm) driver problems, but enough of a pain that I can't recommend Linux for the Masses yet.
--Dave